Author: Andrew Marshall

Introduction

Benzodiazepine overdose describes the ingestion of one of the drugs in the benzodiazepine class in quantities greater than are recommended or generally practiced.

The most common symptoms of overdose include central nervous system (CNS) depression, impaired balance, ataxia, and slurred speech. Severe symptoms include coma and respiratory depression. Supportive care is the mainstay of treatment of benzodiazepine overdose. There is an antidote, flumazenil, but its use is controversial.

Deaths from single-drug benzodiazepine overdoses occur infrequently, particularly after the point of hospital admission. However, combinations of high doses of benzodiazepines with alcohol, barbiturates, opioids or tricyclic antidepressants are particularly dangerous, and may lead to severe complications such as coma or death. In 2013, benzodiazepines were involved in 31% of the estimated 22,767 deaths from prescription drug overdose in the United States. The US Food and Drug Administration (FDA) has subsequently issued a black box warning regarding concurrent use of benzodiazepines and opioids. Benzodiazepines are one of the most highly prescribed classes of drugs, and they are commonly used in self-poisoning. Over 10 years in the United Kingdom, 1512 fatal poisonings have been attributed to benzodiazepines with or without alcohol. Temazepam was shown to be more toxic than the majority of benzodiazepines. An Australian (1995) study found oxazepam less toxic and less sedative, and temazepam more toxic and more sedative, than most benzodiazepines in overdose.

Refer to Benzodiazepine Use Disorder, Benzodiazepine Dependence, Benzodiazepine Withdrawal Syndrome, and Long-Term Effects of Benzodiazepine Use.

Signs and Symptoms

Following an acute overdose of a benzodiazepine the onset of symptoms is typically rapid with most developing symptoms within 4 hours. Patients initially present with mild to moderate impairment of central nervous system function. Initial signs and symptoms include intoxication, somnolence, diplopia, impaired balance, impaired motor function, anterograde amnesia, ataxia, and slurred speech. Most patients with pure benzodiazepine overdose will usually only exhibit these mild CNS symptoms. Paradoxical reactions such as anxiety, delirium, combativeness, hallucinations, and aggression can also occur following benzodiazepine overdose. Gastrointestinal symptoms such as nausea and vomiting have also been occasionally reported.

Cases of severe overdose have been reported and symptoms displayed might include prolonged deep coma or deep cyclic coma, apnoea, respiratory depression, hypoxemia, hypothermia, hypotension, bradycardia, cardiac arrest, and pulmonary aspiration, with the possibility of death. Severe consequences are rare following overdose of benzodiazepines alone but the severity of overdose is increased significantly if benzodiazepines are taken in overdose in combination with other medications. Significant toxicity may result following recreation drug misuse in conjunction with other CNS depressants such as opioids or alcohol. The duration of symptoms following overdose is usually between 12 and 36 hours in the majority of cases. The majority of drug-related deaths involve misuse of heroin or other opioids in combination with benzodiazepines or other CNS depressant drugs. In most cases of fatal overdose it is likely that lack of opioid tolerance combined with the depressant effects of benzodiazepines is the cause of death.

The symptoms of an overdose such as sleepiness, agitation and ataxia occur much more frequently and severely in children. Hypotonia may also occur in severe cases.

Toxicity

Benzodiazepines have a wide therapeutic index and taken alone in overdose rarely cause severe complications or fatalities. More often than not, a patient who inadvertently takes more than the prescribed dose will simply feel drowsy and fall asleep for a few hours. Benzodiazepines taken in overdose in combination with alcohol, barbiturates, opioids, tricyclic antidepressants, or sedating antipsychotics, anticonvulsants, or antihistamines are particularly dangerous. Additionally, emergency department visits involving benzodiazepines compared to other sedative-hypnotics have much higher odds of hospitalisation, patient transfer, or death. In the case of alcohol and barbiturates, not only do they have an additive effect but they also increase the binding affinity of benzodiazepines to the benzodiazepine binding site, which results in a very significant potentiation of the CNS and respiratory depressant effects. In addition, the elderly and those with chronic illnesses are much more vulnerable to lethal overdose with benzodiazepines. Fatal overdoses can occur at relatively low doses in these individuals.

Comparability

The various benzodiazepines differ in their toxicity since they produce varying levels of sedation in overdose. A 1993 British study of deaths during the 1980s found flurazepam and temazepam more frequently involved in drug-related deaths, causing more deaths per million prescriptions than other benzodiazepines. Flurazepam, now rarely prescribed in the United Kingdom and Australia, had the highest fatal toxicity index of any benzodiazepine (15.0), followed by temazepam (11.9), versus benzodiazepines overall (5.9), taken with or without alcohol. An Australian (1995) study found oxazepam less toxic and less sedative, and temazepam more toxic and more sedative, than most benzodiazepines in overdose. An Australian study (2004) of overdose admissions between 1987 and 2002 found alprazolam, which happens to be the most prescribed benzodiazepine in the US by a large margin, to be more toxic than diazepam and other benzodiazepines. They also cited a review of the Annual Reports of the American Association of Poison Control Centres National Data Collection System, which showed alprazolam was involved in 34 fatal deliberate self-poisonings over 10 years (1992–2001), compared with 30 fatal deliberate self-poisonings involving diazepam. In a New Zealand study (2003) of 200 deaths, Zopiclone, a benzodiazepine receptor agonist, had similar overdose potential as benzodiazepines.

Pathophysiology

Benzodiazepines bind to a specific benzodiazepine receptor, thereby enhancing the effect of the neurotransmitter gamma-aminobutyric acid (GABA) and causing CNS depression. In overdose situations this pharmacological effect is extended leading to a more severe CNS depression and potentially coma or cardiac arrest. Benzodiazepine-overdose-related coma may be characterised by an alpha pattern with the central somatosensory conduction time (CCT) after median nerve stimulation being prolonged and the N20 to be dispersed. Brain-stem auditory evoked potentials demonstrate delayed interpeak latencies (IPLs) I-III, III-V and I-V. Toxic overdoses of benzodiazepines therefore cause prolonged CCT and IPLs.

Diagnosis

The diagnosis of benzodiazepine overdose may be difficult, but is usually made based on the clinical presentation of the patient along with a history of overdose. Obtaining a laboratory test for benzodiazepine blood concentrations can be useful in patients presenting with CNS depression or coma of unknown origin. Techniques available to measure blood concentrations include thin layer chromatography, gas liquid chromatography with or without a mass spectrometer, and radioimmunoassay. Blood benzodiazepine concentrations, however, do not appear to be related to any toxicological effect or predictive of clinical outcome. Blood concentrations are, therefore, used mainly to confirm the diagnosis rather than being useful for the clinical management of the patient.

Treatment

Medical observation and supportive care are the mainstay of treatment of benzodiazepine overdose. Although benzodiazepines are absorbed by activated charcoal, gastric decontamination with activated charcoal is not beneficial in pure benzodiazepine overdose as the risk of adverse effects would outweigh any potential benefit from the procedure. It is recommended only if benzodiazepines have been taken in combination with other drugs that may benefit from decontamination. Gastric lavage (stomach pumping) or whole bowel irrigation are also not recommended. Enhancing elimination of the drug with haemodialysis, hemoperfusion, or forced diuresis is unlikely to be beneficial as these procedures have little effect on the clearance of benzodiazepines due to their large volume of distribution and lipid solubility.

Supportive Measures

Supportive measures include observation of vital signs, especially Glasgow Coma Scale and airway patency. IV access with fluid administration and maintenance of the airway with intubation and artificial ventilation may be required if respiratory depression or pulmonary aspiration occurs. Supportive measures should be put in place prior to administration of any benzodiazepine antagonist in order to protect the patient from both the withdrawal effects and possible complications arising from the benzodiazepine. A determination of possible deliberate overdose should be considered with appropriate scrutiny, and precautions taken to prevent any attempt by the patient to commit further bodily harm. Hypotension is corrected with fluid replacement, although catecholamines such as norepinephrine or dopamine may be required to increase blood pressure. Bradycardia is treated with atropine or an infusion of norepinephrine to increase coronary blood flow and heart rate.

Flumazenil

Flumazenil (Romazicon) is a competitive benzodiazepine receptor antagonist that can be used as an antidote for benzodiazepine overdose. Its use, however, is controversial as it has numerous contraindications. It is contraindicated in patients who are on long-term benzodiazepines, those who have ingested a substance that lowers the seizure threshold, or in patients who have tachycardia, widened QRS complex on ECG, anticholinergic signs, or a history of seizures. Due to these contraindications and the possibility of it causing severe adverse effects including seizures, adverse cardiac effects, and death, in the majority of cases there is no indication for the use of flumazenil in the management of benzodiazepine overdose as the risks in general outweigh any potential benefit of administration. It also has no role in the management of unknown overdoses. In addition, if full airway protection has been achieved, a good outcome is expected, and therefore flumazenil administration is unlikely to be required.

Flumazenil is very effective at reversing the CNS depression associated with benzodiazepines but is less effective at reversing respiratory depression. One study found that only 10% of the patient population presenting with a benzodiazepine overdose are suitable candidates for flumazenil. In this select population who are naïve to and overdose solely on a benzodiazepine, it can be considered. Due to its short half life, the duration of action of flumazenil is usually less than 1 hour, and multiple doses may be needed. When flumazenil is indicated the risks can be reduced or avoided by slow dose titration of flumazenil. Due to risks and its many contraindications, flumazenil should be administered only after discussion with a medical toxicologist.

Epidemiology

In a Swedish (2003) study benzodiazepines were implicated in 39% of suicides by drug poisoning in the elderly 1992-1996. Nitrazepam and flunitrazepam accounted for 90% of benzodiazepine implicated suicides. In cases where benzodiazepines contributed to death, but were not the sole cause, drowning, typically in the bath, was a common method used. Benzodiazepines were the predominant drug class in suicides in this review of Swedish death certificates. In 72% of the cases, benzodiazepines were the only drug consumed. Thus, many of deaths associated with benzodiazepine overdoses may not be a direct result of the toxic effects but either due to being combined with other drugs or used as a tool to complete suicide using a different method, e.g. drowning.

In a Swedish retrospective study of deaths of 1987, in 159 of 1587 autopsy cases benzodiazepines were found. In 44 of these cases the cause of death was natural causes or unclear. The remaining 115 deaths were due to accidents (N = 16), suicide (N = 60), drug addiction (N = 29) or alcoholism (N = 10). In a comparison of suicides and natural deaths, the concentrations both of flunitrazepam and nitrazepam (sleeping medications) were significantly higher among the suicides. In four cases benzodiazepines were the sole cause of death.

In Australia, a study of 16 deaths associated with toxic concentrations of benzodiazepines during the period of 5 years leading up to July 1994 found pre-existing natural disease as a feature of 11 cases; 14 cases were suicides. Cases where other drugs, including ethanol, had contributed to the death were excluded. In the remaining five cases, death was caused solely by benzodiazepines. Nitrazepam and temazepam were the most prevalent drugs detected, followed by oxazepam and flunitrazepam. A review of self poisonings of 12 months 1976-1977 in Auckland, New Zealand, found benzodiazepines implicated in 40% of the cases. A 1993 British study found flurazepam and temazepam to have the highest number of deaths per million prescriptions among medications commonly prescribed in the 1980s. Flurazepam, now rarely prescribed in the United Kingdom and Australia, had the highest fatal toxicity index of any benzodiazepine (15.0) followed by Temazepam (11.9), versus 5.9 for benzodiazepines overall, taken with or without alcohol.

Etizolam overdose deaths are rising – for instance, the National Records of Scotland report on drug-related deaths, implicated 548 deaths from ‘street’ Etizolam in 2018, almost double the number from 2017 (299) and only six years from the first recorded death (in 2012). The 548 deaths were 45% of all drug-related deaths in Scotland in 2018.

Introduction

Benzodiazepine dependence defines a situation in which one has developed one or more of either tolerance, withdrawal symptoms, drug seeking behaviours, such as continued use despite harmful effects, and maladaptive pattern of substance use.

In the case of benzodiazepine dependence, however, the continued use seems to be associated with the avoidance of unpleasant withdrawal reaction rather than from the pleasurable effects of the drug. Benzodiazepine dependence can develop with long-term use, even at low therapeutic doses, without the described dependence behaviour.

Addiction consists of people misusing or craving the drug not to relieve withdrawal symptoms, but to experience its euphoric or intoxicating effects. It is necessary to distinguish between addiction to and abuse of benzodiazepines and physical dependence on them. The increased GABA inhibition on the neural systems caused by benzodiazepines is counteracted by the body’s development of tolerance to the drug’s effects; the development of tolerance occurs as a result of neuroadaptations, which result in decreased GABA activity and increased excitability of the glutamate system; these adaptations occur as a result of the body trying to overcome the central nervous system depressant effects of the drug to restore homeostasis. When benzodiazepines are stopped, these neuroadaptations are “unmasked” leading to hyper-excitability of the nervous system and the appearance of withdrawal symptoms.

Therapeutic dose dependence is the largest category of people dependent on benzodiazepines. These individuals typically do not escalate their doses to high levels and generally use their medication as intended by their prescriber. Smaller groups include patients escalating their dosage to higher levels and drug misusers as well. Tolerance develops within days or weeks to the anticonvulsant, hypnotic, muscle relaxant and after 4 months there is little evidence that benzodiazepines retain their anxiolytic properties. Some authors, however, disagree and feel that benzodiazepines retain their anxiolytic properties. Long-term benzodiazepine treatment may remain necessary in certain clinical conditions.

Numbers of benzodiazepine prescriptions have been declining, due primarily to concerns of dependence. In the short term, benzodiazepines can be effective drugs for acute anxiety or insomnia. With longer-term use, other therapies, both pharmacological and psychotherapeutic, become more effective. This is in part due to the greater effectiveness over time of other forms of therapy, and also due to the eventual development of pharmacological benzodiazepine tolerance.

Brief History

Previously, physical dependence on benzodiazepines was largely thought to occur only in people on high-therapeutic-dose ranges. Low- or normal-dose dependence was not suspected until the 1970s, and it was not until the early 1980s that it was confirmed. Low-dose dependence has now been clearly demonstrated in both animal studies and human studies, and is a recognized clinical disadvantage of benzodiazepines. Severe withdrawal syndromes can occur from these low doses of benzodiazepines even after gradual dose reduction. An estimated 30-45% of chronic low-dose benzodiazepine users are dependent and it has been recommended that benzodiazepines even at low dosage be prescribed for a maximum of 7-14 days to avoid dependence. As a result, the global trend is toward strict regulations for the prescription of benzodiazepines due to this risk of low-dose dependence.

Some controversy remains, however, in the medical literature as to the exact nature of low-dose dependence and the difficulty in getting patients to discontinue their benzodiazepines, with some papers attributing the problem to predominantly drug-seeking behaviour and drug craving, whereas other papers having found the opposite, attributing the problem to a problem of physical dependence with drug-seeking and craving not being typical of low-dose benzodiazepine users.

Signs and Symptoms

Refer to Benzodiazepine Withdrawal Syndrome.

The signs and symptoms of benzodiazepine dependence include feeling unable to cope without the drug, unsuccessful attempts to cut down or stop benzodiazepine use, tolerance to the effects of benzodiazepines, and withdrawal symptoms when not taking the drug. Some withdrawal symptoms that may appear include anxiety, depressed mood, depersonalisation, derealisation, sleep disturbance, hypersensitivity to touch and pain, tremor, shakiness, muscular aches, pains, twitches, and headache. Benzodiazepine dependence and withdrawal have been associated with suicide and self-harming behaviours, especially in young people. The Department of Health substance misuse guidelines recommend monitoring for mood disorder in those dependent on or withdrawing from benzodiazepines.

Benzodiazepine dependence is a frequent complication for those prescribed for or using for longer than four weeks, with physical dependence and withdrawal symptoms being the most common problem, but also occasionally drug-seeking behaviour. Withdrawal symptoms include anxiety, perceptual disturbances, distortion of all the senses, dysphoria, and, in rare cases, psychosis and epileptic seizures.

Elderly

Long-term use and benzodiazepine dependence is a serious problem in the elderly. Failure to treat benzodiazepine dependence in the elderly can cause serious medical complications. The elderly have less cognitive reserve and are more sensitive to the short (e.g. in between dose withdrawal) and protracted withdrawal effects of benzodiazepines, as well as the side-effects both from short-term and long-term use. This can lead to excessive contact with their doctor. Research has found that withdrawing elderly people from benzodiazepines leads to a significant reduction in doctor visits per year, it is presumed, due to an elimination of drug side-effects and withdrawal effects.

Tobacco and alcohol are the most common substances that elderly people get a dependence on or misuse. The next-most-common substance that elderly people develop a drug dependence to or misuse is benzodiazepines. Drug-induced cognitive problems can have serious consequences for elderly people and can lead to confusional states and “pseudo-dementia”. About 10% of elderly patients referred to memory clinics actually have a drug-induced cause that most often is benzodiazepines. Benzodiazepines have also been linked to an increased risk of road traffic accidents and falls in the elderly. The long-term effects of benzodiazepines are still not fully understood in the elderly or any age group. Long-term benzodiazepine use is associated with attentional and visuospatial functional impairments. Withdrawal from benzodiazepines can lead to improved alertness and decreased forgetfulness in the elderly. Withdrawal led to statistical significant improvements in memory function and performance related skills in those having withdrawn successfully from benzodiazepines, whereas those having remained on benzodiazepines experienced worsening symptoms. People having withdrawn from benzodiazepines also felt their sleep was more refreshing, making statements such as “I feel sharper when I wake up” or “I feel better, more awake”, or “It used to take me an hour to fully wake up.” This suggests that benzodiazepines may actually make insomnia worse in the elderly.

Cause

Tolerance occurs to the muscle-relaxant, anticonvulsant, and sleep-inducing effects of benzodiazepines, and upon cessation a benzodiazepine withdrawal syndrome occurs. This can lead to benzodiazepines being taken for longer than originally intended, as people continue to take the drugs over a long period of time to suppress withdrawal symptoms. Some people use benzodiazepines at very high doses and devote a lot of time to doing so, satisfying the diagnostic criteria in DSM V for substance use disorder. Another group of people include those on low to moderate therapeutic doses of benzodiazepines who do not use their benzodiazepines differently than recommended by their prescriber but develop a physical tolerance and benzodiazepine dependence. A considerable number of individuals using benzodiazepines for insomnia escalate their dosage, sometimes above therapeutically-prescribed dose levels. Tolerance to the anxiolytic effect of benzodiazepines has been clearly demonstrated in rats. In humans, there is little evidence that benzodiazepines retain their anti-anxiety effects beyond four months of continuous treatment; there is evidence that suggests that long-term use of benzodiazepines may actually worsen anxiety, which in turn may lead to dosage escalation, with one study finding 25% of patients escalated their dosage. Some authors, however, consider benzodiazepines to be effective long-term; however, it is more likely that the drugs are acting to prevent rebound anxiety withdrawal effects which can be mistaken as continued drug efficacy. Tolerance to the anticonvulsant and muscle-relaxing effects of benzodiazepines occurs within a few weeks in most patients.

Risk Factors

The risk factors for benzodiazepine dependence are long-term use beyond four weeks, use of high doses, use of potent short-acting benzodiazepines, dependent personalities, and proclivity for substance use. Use of short-acting benzodiazepines leads to repeated withdrawal effects that are alleviated by the next dose, which reinforce in the individual the dependence. A physical dependence develops more quickly with higher potency benzodiazepines such as alprazolam (Xanax) than with lower potency benzodiazepines such as chlordiazepoxide (Librium).

Symptom severity is worse with the use of high doses, or with benzodiazepines of high potency or short half-life. Other cross-tolerant sedative hypnotics, such as barbiturates or alcohol, increase the risk of benzodiazepine dependence. Similar to opioids’ use for pain, therapeutic use of benzodiazepines rarely leads to a substance use disorder.

Refer to Benzodiazepine Overdose and Long-Term Effects of Benzodiazepine Use.

Mechanism

Tolerance and Physical Dependence

Tolerance develops rapidly to the sleep-inducing effects of benzodiazepines. The anticonvulsant and muscle-relaxant effects last for a few weeks before tolerance develops in most individuals. Tolerance results in a desensitization of GABA receptors and an increased sensitization of the excitatory neurotransmitter system, such as NMDA glutamate receptors. These changes occur as a result of the body trying to overcome the drug’s effects. Other changes that occur are the reduction of the number of GABA receptors (downregulation) as well as possibly long-term changes in gene transcription coding of brain cells. The differing speed at which tolerance occurs to the therapeutic effects of benzodiazepines can be explained by the speed of changes in the range of neurotransmitter systems and subsystems that are altered by chronic benzodiazepine use. The various neurotransmitter systems and subsystems may reverse tolerance at different speeds, thus explaining the prolonged nature of some withdrawal symptoms. As a result of a physical dependence that develops due to tolerance, a characteristic benzodiazepine withdrawal syndrome often occurs after removal of the drug or a reduction in dosage. Changes in the expression of neuropeptides such as corticotropin-releasing hormone and neuropeptide Y may play a role in benzodiazepine dependence. Individuals taking daily benzodiazepine drugs have a reduced sensitivity to further additional doses of benzodiazepines. Tolerance to benzodiazepines can be demonstrated by injecting diazepam into long-term users. In normal subjects, increases in growth hormone occurs, whereas, in benzodiazepine-tolerant individuals, this effect is blunted.

Animal studies have shown that repeated withdrawal from benzodiazepines leads to increasingly severe withdrawal symptoms, including an increased risk of seizures; this phenomenon is known as kindling. Kindling phenomena are well established for repeated ethanol (alcohol) withdrawal; alcohol has a very similar mechanism of tolerance and withdrawal to benzodiazepines, involving the GABA_A, NMDA, and AMPA receptors.

The shift of benzodiazepine receptors to an inverse agonist state after chronic treatment leads the brain to be more sensitive to excitatory drugs or stimuli. Excessive glutamate activity can result in excitotoxicity, which may result in neurodegeneration. The glutamate receptor subtype NMDA is well known for its role in causing excito-neurotoxicity. The glutamate receptor subtype AMPA is believed to play an important role in neuronal kindling as well as excitotoxicity during withdrawal from alcohol as well as benzodiazepines. It is highly possible that NMDA receptors are involved in the tolerance to some effects of benzodiazepines.

Animal studies have found that glutamergic changes as a result of benzodiazepine use are responsible for a delayed withdrawal syndrome, which in mice peaks 3 days after cessation of benzodiazepines. This was demonstrated by the ability to avoid the withdrawal syndrome by the administration of AMPA antagonists. It is believed that different glutamate subreceptors, e.g. NMDA and AMPA, are responsible for different stages/time points of the withdrawal syndrome. NMDA receptors are upregulated in the brain as a result of benzodiazepine tolerance. AMPA receptors are also involved in benzodiazepine tolerance and withdrawal. A decrease in benzodiazepine binding sites in the brain may also occur as part of benzodiazepine tolerance.

Cross Tolerance

Benzodiazepines share a similar mechanism of action with various sedative compounds that act by enhancing the GABA_A receptor. Cross tolerance means that one drug will alleviate the withdrawal effects of another. It also means that tolerance of one drug will result in tolerance of another similarly-acting drug. Benzodiazepines are often used for this reason to detoxify alcohol-dependent patients and can have life-saving properties in preventing or treating severe life-threatening withdrawal syndromes from alcohol, such as delirium tremens. However, although benzodiazepines can be very useful in the acute detoxification of alcoholics, benzodiazepines in themselves act as positive reinforcers in alcoholics, by increasing the desire for alcohol. Low doses of benzodiazepines were found to significantly increase the level of alcohol consumed in alcoholics. Alcoholics dependent on benzodiazepines should not be abruptly withdrawn but be very slowly withdrawn from benzodiazepines, as over-rapid withdrawal is likely to produce severe anxiety or panic, which is well known for being a relapse risk factor in recovering alcoholics.

There is cross tolerance between alcohol, the benzodiazepines, the barbiturates, the nonbenzodiazepine drugs, and corticosteroids, which all act by enhancing the GABA_A receptor’s function via modulating the chloride ion channel function of the GABA_A receptor.

Neuroactive steroids, e.g. progesterone and its active metabolite allopregnanolone, are positive modulators of the GABA_A receptor and are cross tolerant with benzodiazepines. The active metabolite of progesterone has been found to enhance the binding of benzodiazepines to the benzodiazepine binding sites on the GABA_A receptor. The cross-tolerance between GABA_A receptor positive modulators, including benzodiazepines, occurs because of the similar mechanism of action and the subunit changes that occur from chronic use from one or more of these compounds in expressed receptor isoforms. Abrupt withdrawal from any of these compounds, e.g. barbiturates, benzodiazepines, alcohol, corticosteroids, neuroactive steroids, and nonbenzodiazepines, precipitate similar withdrawal effects characterized by central nervous system hyper-excitability, resulting in symptoms such as increased seizure susceptibility and anxiety. While many of the neuroactive steroids do not produce full tolerance to their therapeutic effects, cross-tolerance to benzodiazepines still occurs as had been demonstrated between the neuroactive steroid ganaxolone and diazepam. Alterations of levels of neuroactive steroids in the body during the menstrual cycle, menopause, pregnancy, and stressful circumstances can lead to a reduction in the effectiveness of benzodiazepines and a reduced therapeutic effect. During withdrawal of neuroactive steroids, benzodiazepines become less effective.

Physiology of Withdrawal

Withdrawal symptoms are a normal response in individuals having chronically used benzodiazepines, and an adverse effect and result of drug tolerance. Symptoms typically emerge when dosage of the drug is reduced. GABA is the second-most-common neurotransmitter in the central nervous system (the most common being glutamate) and by far the most abundant inhibitory neurotransmitter; roughly one-quarter to one-third of synapses use GABA. The use of benzodiazepines has a profound effect on almost every aspect of brain and body function, either directly or indirectly.

Benzodiazepines cause a decrease in norepinephrine (noradrenaline), serotonin, acetylcholine, and dopamine. These neurotransmitters are needed for normal memory, mood, muscle tone and coordination, emotional responses, endocrine gland secretions, heart rate, and blood pressure control. With chronic benzodiazepine use, tolerance develops rapidly to most of its effects, so that, when benzodiazepines are withdrawn, various neurotransmitter systems go into overdrive due to the lack of inhibitory GABA-ergic activity. Withdrawal symptoms then emerge as a result, and persist until the nervous system physically reverses the adaptions (physical dependence) that have occurred in the CNS.

Withdrawal symptoms typically consist of a mirror image of the drug’s effects: Sedative effects and suppression of REM and SWS stages of sleep can be replaced by insomnia, nightmares, and hypnogogic hallucinations; its antianxiety effects are replaced with anxiety and panic; muscle-relaxant effects are replaced with muscular spasms or cramps; and anticonvulsant effects are replaced with seizures, especially in cold turkey or overly-rapid withdrawal.

Benzodiazepine withdrawal represents in part excitotoxicity to brain neurons. Rebound activity of the hypothalamic-pituitary-adrenocortical axis also plays an important role in the severity of benzodiazepine withdrawal. Tolerance and the resultant withdrawal syndrome may be due to alterations in gene expression, which results in long-term changes in the function of the GABAergic neuronal system.

During withdrawal from full or partial agonists, changes occur in benzodiazepine receptor with upregulation of some receptor subtypes and downregulation of other receptor subtypes.

Withdrawal

Refer to Benzodiazepine Withdrawal Syndrome.

Long-term use of benzodiazepines leads to increasing physical and mental health problems, and as a result, discontinuation is recommended for many long-term users. The withdrawal syndrome from benzodiazepines can range from a mild and short-lasting syndrome to a prolonged and severe syndrome. Withdrawal symptoms can lead to continued use of benzodiazepines for many years, long after the original reason for taking benzodiazepines has passed. Many patients know that the benzodiazepines no longer work for them but are unable to discontinue benzodiazepines because of withdrawal symptoms.

Withdrawal symptoms can emerge despite slow reduction but can be reduced by a slower rate of withdrawal. As a result, withdrawal rates have been recommended to be customized to each individual patient. The time needed to withdrawal can vary from a couple of months to a year or more and often depends on length of use, dosage taken, lifestyle, health, and social and environmental stress factors.

Diazepam is often recommended due to its long elimination half-life and also because of its availability in low potency doses. The non-benzodiazepine Z drugs such as zolpidem, zaleplon, and zopiclone should not be used as a replacement for benzodiazepines, as they have a similar mechanism of action and can induce a similar dependence. The pharmacological mechanism of benzodiazepine tolerance and dependence is the internalisation (removal) of receptor site in the brain and changes in gene transcription codes in the brain.

With long-term use and during withdrawal of benzodiazepines, treatment-emergent depression and emotional blunting may emerge and sometimes also suicidal ideation. There is evidence that the higher the dose used the more likely it is benzodiazepine use will induce these feelings. Reducing the dose or discontinuing benzodiazepines may be indicated in such cases. Withdrawal symptoms can persist for quite some time after discontinuing benzodiazepines. Some common protracted withdrawal symptoms include anxiety, depression, insomnia, and physical symptoms such as gastrointestinal, neurologic, and musculoskeletal effects. The protracted withdrawal state may still occur despite slow titration of dosage. It is believed that the protracted withdrawal effects are due to persisting neuroadaptations.

Diagnosis

For a diagnosis of benzodiazepine dependence to be made, the ICD-10 requires that at least 3 of the below criteria are met and that they have been present for at least a month, or, if less than a month, that they appeared repeatedly during a 12-month period.

• Behavioural, cognitive, and physiological phenomena that are associated with the repeated use and that typically include a strong desire to take the drug.
• Difficulty controlling use.
• Continued use despite harmful consequences.
• Preference given to drug use rather than to other activities and obligations.
• Increased tolerance to effects of the drug and sometimes a physical withdrawal state.

These diagnostic criteria are good for research purposes, but, in everyday clinical practice, they should be interpreted according to clinical judgement. In clinical practice, benzodiazepine dependence should be suspected in those having used benzodiazepines for longer than a month, in particular, if they are from a high-risk group. The main factors associated with an increased incidence of benzodiazepine dependence include:

• Dose.
• Duration.
• Concomitant use of antidepressants.

Benzodiazepine dependence should be suspected also in individuals having substance use disorders including alcohol, and should be suspected in individuals obtaining their own supplies of benzodiazepines. Benzodiazepine dependence is almost certain in individuals who are members of a tranquiliser self-help group.

Research has found that about 40% of people with a diagnosis of benzodiazepine dependence are not aware that they are dependent on benzodiazepines, whereas about 11% of people judged not to be dependent believe that they are. When assessing a person for benzodiazepine dependence, asking specific questions rather than questions based on concepts is recommended by experts as the best approach of getting a more accurate diagnosis. For example, asking persons if they “think about the medication at times of the day other than when they take the drug” would provide a more meaningful answer than asking “do you think you are psychologically dependent?”. The Benzodiazepine Dependence Self Report Questionnaire is one questionnaire used to assess and diagnose benzodiazepine dependence.

Definition

Benzodiazepine dependence is the condition resulting from repeated use of benzodiazepine drugs. It can include both a physical dependence as well as a psychological dependence and is typified by a withdrawal syndrome upon a fall in blood plasma levels of benzodiazepines, e.g. during dose reduction or abrupt withdrawal.

Prevention

Due to the risk of developing tolerance, dependence, and adverse health effects, such as cognitive impairment, benzodiazepines are indicated for short-term use only – a few weeks, followed by a gradual dose reduction.

The Committee on the Review of Medicines (UK)

The Committee on the Review of Medicines carried out a review into benzodiazepines due to significant concerns of tolerance, drug dependence, benzodiazepine withdrawal problems, and other adverse effects and published the results in the British Medical Journal in March 1980. The committee found that benzodiazepines do not have any antidepressant or analgesic properties and are, therefore, unsuitable treatments for conditions such as depression, tension headaches, and dysmenorrhea. Benzodiazepines are also not beneficial in the treatment of psychosis. The committee also recommended against benzodiazepines for use in the treatment of anxiety or insomnia in children.

The committee was in agreement with the Institute of Medicine (US) and the conclusions of a study carried out by the White House Office of Drug Policy and the National Institute on Drug Abuse (US) that there is little evidence that long-term use of benzodiazepine hypnotics are beneficial in the treatment of insomnia due to the development of tolerance. Benzodiazepines tend to lose their sleep-promoting properties within 3-14 days of continuous use, and, in the treatment of anxiety, the committee found that there was little convincing evidence that benzodiazepines retains efficacy in the treatment of anxiety after 4 months of continuous use due to the development of tolerance.

The committee found that the regular use of benzodiazepines causes the development of dependence characterized by tolerance to the therapeutic effects of benzodiazepines and the development of the benzodiazepine withdrawal syndrome including symptoms such as anxiety, apprehension, tremors, insomnia, nausea, and vomiting upon cessation of benzodiazepine use. Withdrawal symptoms tend to develop within 24 hours upon cessation of short-acting benzodiazepines, and 3-10 days after cessation of longer-acting benzodiazepines. Withdrawal effects could even occur after treatment lasting only 2 weeks at therapeutic dose levels; however, withdrawal effects tend to occur with habitual use beyond 2 weeks and are more likely the higher the dose. The withdrawal symptoms may appear to be similar to the original condition.

The committee recommended that all benzodiazepine treatment be withdrawn gradually and recommended that benzodiazepine treatment be used only in carefully selected patients and that therapy be limited to short-term use only. It was noted in the review that alcohol can potentiate the central nervous system-depressant effects of benzodiazepines and should be avoided. The central nervous system-depressant effects of benzodiazepines may make driving or operating machinery dangerous, and the elderly are more prone to these adverse effects. High single doses or repeated low doses have been reported to produce hypotonia, poor sucking, and hypothermia in the neonate, and irregularities in the foetal heart. The committee recommended that benzodiazepines be avoided in lactation.

The committee recommended that withdrawal from benzodiazepines be gradual, as abrupt withdrawal from high doses of benzodiazepines may cause confusion, toxic psychosis, convulsions, or a condition resembling delirium tremens. Abrupt withdrawal from lower doses may cause depression, nervousness, rebound insomnia, irritability, sweating, and diarrhoea.

The committee also made a mistake concluding:

on the present available evidence, the true addiction potential of benzodiazepines was low. The number dependent on the benzodiazepines in the UK from 1960 to 1977 has been estimated to be 28 persons. This is equivalent to a dependence rate of 5-10 cases per million patient months.

Treatment

Benzodiazepines are regarded as a highly addictive drug class. A psychological and physical dependence can develop in as short as a few weeks but may take years to develop in other individuals. Patients wanting to withdraw from benzodiazepines typically receive little advice or support, and such withdrawal should be by small increments over a period of months.

Benzodiazepines are usually prescribed only short-term, as there is little justification for their prescribing long-term. Some doctors however, disagree and believe long-term use beyond 4 weeks is sometimes justified, although there is little data to support this viewpoint. Such viewpoints are a minority in the medical literature.

There is no evidence that “drug holidays” or periods of abstinence reduced the risk of dependence; there is evidence from animal studies that such an approach does not prevent dependence from happening. Use of short-acting benzodiazepines is associated with interdose withdrawal symptoms. Kindling has clinical relevance with regard to benzodiazepines; for example, there is an increasing shift to use of benzodiazepines with a shorter half-life and intermittent use, which can result in interdose withdrawal and rebound effects.

Cognitive Behavioural Therapy

Cognitive behavioural therapy (CBT) has been found to be more effective for the long-term management of insomnia than sedative hypnotic drugs. No formal withdrawal programmes for benzodiazepines exists with local providers in the UK. Meta-analysis of published data on psychological treatments for insomnia show a success rate between 70 and 80%. A large-scale trial utilising CBT in chronic users of sedative hypnotics including nitrazepam, temazepam, and zopiclone found CBT to be a significantly more effective long-term treatment for chronic insomnia than sedative hypnotic drugs. Persisting improvements in sleep quality, sleep onset latency, increased total sleep, improvements in sleep efficiency, significant improvements in vitality, physical and mental health at 3-, 6-, and 12-month follow-ups were found in those receiving CBT. A marked reduction in total sedative hypnotic drug use was found in those receiving CBT, with 33% reporting zero hypnotic drug use. Age has been found not to be a barrier to successful outcome of CBT. It was concluded that CBT for the management of chronic insomnia is a flexible, practical, and cost-effective treatment, and it was also concluded that CBT leads to a reduction of benzodiazepine drug intake in a significant number of patients.

Chronic use of hypnotic medications is not recommended due to their adverse effects on health and the risk of dependence. A gradual taper is usual clinical course in getting people off of benzodiazepines, but, even with gradual reduction, a large proportion of people fail to stop taking benzodiazepines. The elderly are particularly sensitive to the adverse effects of hypnotic medications. A clinical trial in elderly people dependent on benzodiazepine hypnotics showed that the addition of CBT to a gradual benzodiazepine reduction program increased the success rate of discontinuing benzodiazepine hypnotic drugs from 38% to 77% and at the 12-month follow-up from 24% to 70%. The paper concluded that CBT is an effective tool for reducing hypnotic use in the elderly and reducing the adverse health effects that are associated with hypnotics such as drug dependence, cognitive impairments, and increased road traffic accidents.

A study of patients undergoing benzodiazepine withdrawal who had a diagnosis of generalized anxiety disorder showed that those having received CBT had a very high success rate of discontinuing benzodiazepines compared to those not having receive CBT. This success rate was maintained at the 12-month follow-up. Furthermore, it was found that, in patients having discontinued benzodiazepines, they no longer met the diagnosis of general anxiety disorder, and that the number of patients no longer meeting the diagnosis of general anxiety disorder was higher in the group having received CBT. Thus, CBT can be an effective tool to add to a gradual benzodiazepine dosage reduction programme leading to improved and sustained mental health benefits (although this disputed by some).

Letter to Patients

Sending a letter to patients warning of the adverse effects of long-term use of benzodiazepines and recommending dosage reduction has been found to be successful and a cost-effective strategy in reducing benzodiazepine consumption in general practice. Within a year of the letter’s going out, there was found to be a 17% fall in the number of benzodiazepines being prescribed, with 5% of patients having totally discontinued benzodiazepines. A study in the Netherlands reported a higher success rate by sending a letter to patients who are benzodiazepine-dependent. The results of the Dutch study reported 11.3% of patients discontinuing benzodiazepines completely within a year.

Flumazenil

Flumazenil delivered via slow subcutaneous infusion represents a safe procedure for those withdrawing from long-term, high dose benzodiazepine dependency. It has a low risk of seizures even amongst those who have experienced convulsions when previously attempting benzodiazepine withdrawal.

Epidemiology

Research studies have come to different conclusions on the number of therapeutic dose users who develop a physical dependence and withdrawal syndrome. Researches estimate 20-100% (that’s a wide range) of patients, taking benzodiazepines at therapeutic dosages for the long term, are physically dependent and will experience withdrawal symptoms.

Benzodiazepines can be addictive and induce dependence even at low doses, with 23% becoming addicted within 3 months of use. Benzodiazepine addiction is considered a public health problem. Approximately 68.5% of prescriptions of benzodiazepines originate from local health centres, with psychiatry and general hospitals accounting for 10% each. A survey of general practitioners reported that the reason for initiating benzodiazepines was due to an empathy for the patients suffering and a lack of other therapeutic options rather than patients demanding them. However, long-term use was more commonly at the insistence of the patient, it is presumed, because physical dependence or addiction had developed.

Approximately twice as many women as men are prescribed benzodiazepines. It is believed that this is largely because men typically turned to alcohol to cope with stress and women to prescription drugs. Biased perception of women by male doctors may also play a role in increased prescribing rates to women; however, increased anxiety features in women does not account for the wide gap alone between men and women.

Based on findings in the US from the Treatment Episode Data Set (TEDS), an annual compilation of patient characteristics in substance use disorder treatment facilities in the United States, admissions due to “primary tranquilizer” (including, but not limited to, benzodiazepine-type) drug use increased 79% from 1992 to 2002.

A study published in the British Journal of General Practice in July 2017 found that in a sample taken from a survey conducted in 2014-2015 in Bradford a mean of 0.69% of registered patients had been prescribed benzodiazepines for more than a year. This would suggest that there were around 300,000 long-term users of diazepine in the UK.

Society and Culture

Misuse and Addiction

Refer to Benzodiazepine Use Disorder.

Benzodiazepines are one of the largest classes of illicitly used substances; they are classed as schedule IV controlled drugs because of their recognized medical uses. Across the world the most frequently diverted and non-medically used benzodiazepines include temazepam, diazepam, nimetazepam, nitrazepam, triazolam, flunitrazepam, midazolam, and in the United States alprazolam, clonazepam, and lorazepam.

Benzodiazepines can cause serious addiction problems. A survey of doctors in Senegal found that many doctors feel that their training and knowledge of benzodiazepines is, in general, poor; a study in Dakar found that almost one-fifth of doctors ignored prescribing guidelines regarding short-term use of benzodiazepines, and almost three-quarters of doctors regarded their training and knowledge of benzodiazepines to be inadequate. More training regarding benzodiazepines has been recommended for doctors. Due to the serious concerns of addiction, national governments were recommended to urgently seek to raise knowledge via training about the addictive nature of benzodiazepines and appropriate prescribing of benzodiazepines.

A six-year study on 51 Vietnam veterans who had a substance use disorder related mainly to stimulants (11 people), opiates (26 people), or benzodiazepines (14 people) was carried out to assess psychiatric symptoms related to the specific substances. After six years, people who used opiates had little change in psychiatric symptomatology; five of the people who used stimulants developed psychosis, and eight of the people who used benzodiazepine developed depression. Therefore, long-term benzodiazepine use and dependence seems to carry a negative effect on mental health, with a significant risk of causing depression. Benzodiazepines are also sometimes taken intra-nasally when not recommended for use this way by their prescriber.

In the elderly, alcohol and benzodiazepines are the most commonly used addictive substances, and the elderly population is more susceptible to benzodiazepine withdrawal syndrome and delirium than are younger patients.

Introduction

Benzodiazepine use disorder (BUD), also called misuse or abuse, is the use of benzodiazepines without a prescription, often for recreational purposes, which poses risks of dependence, withdrawal and other long-term effects.

Benzodiazepines are one of the more common prescription drugs used recreationally. When used recreationally benzodiazepines are usually administered orally but sometimes they are taken intranasally or intravenously. Recreational use produces effects similar to alcohol intoxication.

In tests in pentobarbital trained rhesus monkeys benzodiazepines produced effects similar to barbiturates. In a 1991 study, triazolam had the highest self-administration rate in cocaine trained baboons, among the five benzodiazepines examined: alprazolam, bromazepam, chlordiazepoxide, lorazepam, triazolam. A 1985 study found that triazolam and temazepam maintained higher rates of self-injection in both human and animal subjects compared to a variety of other benzodiazepines (others examined: diazepam, lorazepam, oxazepam, flurazepam, alprazolam, chlordiazepoxide, clonazepam, nitrazepam, flunitrazepam, bromazepam, and clorazepate). A 1991 study indicated that diazepam, in particular, had a greater abuse liability among people who were drug abusers than did many of the other benzodiazepines. Some of the available data also suggested that lorazepam and alprazolam are more diazepam-like in having relatively high abuse liability, while oxazepam, halazepam, and possibly chlordiazepoxide, are relatively low in this regard. A 1991-1993 British study found that the hypnotics flurazepam and temazepam were more toxic than average benzodiazepines in overdose. A 1995 study found that temazepam is more rapidly absorbed and oxazepam is more slowly absorbed than most other benzodiazepines. Benzodiazepines have been abused both orally and intravenously. Different benzodiazepines have different abuse potential; the more rapid the increase in the plasma level following ingestion, the greater the intoxicating effect and the more open to abuse the drug becomes. The speed of onset of action of a particular benzodiazepine correlates well with the ‘popularity’ of that drug for abuse. The two most common reasons for preference were that a benzodiazepine was ‘strong’ and that it gave a good ‘high’.

According to Dr. Chris Ford, former clinical director of Substance Misuse Management in General Practice, among drugs of abuse, benzodiazepines are often seen as the ‘bad guys’ by drug and alcohol workers. Illicit users of benzodiazepines have been found to take higher methadone doses, as well as showing more HIV/HCV risk-taking behaviour, greater poly-drug use, higher levels of psychopathology and social dysfunction. However, there is only limited research into the adverse effects of benzodiazepines in drug misusers and further research is needed to demonstrate whether this is the result of cause or effect.

Signs and Symptoms

Refer to Benzodiazepine Withdrawal Syndrome and Benzodiazepine Dependence.

Sedative-hypnotics such as alcohol, benzodiazepines, and the barbiturates are known for the severe physical dependence that they are capable of inducing which can result in severe withdrawal effects. This severe neuroadaptation is even more profound in high dose drug users and misusers. A high degree of tolerance often occurs in chronic benzodiazepine abusers due to the typically high doses they consume which can lead to a severe benzodiazepine dependence. The benzodiazepine withdrawal syndrome seen in chronic high dose benzodiazepine abusers is similar to that seen in therapeutic low dose users but of a more severe nature. Extreme antisocial behaviours in obtaining continued supplies and severe drug-seeking behaviour when withdrawals occur. The severity of the benzodiazepine withdrawal syndrome has been described by one benzodiazepine drug misuser who stated that:

I’d rather withdraw off heroin any day. If I was withdrawing from benzos you could offer me a gram of heroin or just 20mg of diazepam and I’d take the diazepam every time – I’ve never been so frightened in my life.

Those who use benzodiazepines intermittently are less likely to develop a dependence and withdrawal symptoms upon dose reduction or cessation of benzodiazepines than those who use benzodiazepines on a daily basis.

Misuse of benzodiazepines is widespread amongst drug misusers; however, many of these people will not require withdrawal management as their use is often restricted to binges or occasional misuse. Benzodiazepine dependence when it occurs requires withdrawal treatment. There is little evidence of benefit from long-term substitution therapy of benzodiazepines, and conversely, there is growing evidence of the harm of long-term use of benzodiazepines, especially higher doses. Therefore, gradual reduction is recommended, titrated against withdrawal symptoms. For withdrawal purposes, stabilisation with a long-acting agent such as diazepam is recommended before commencing withdrawal. Chlordiazepoxide (Librium), a long-acting benzodiazepine, is gaining attention as an alternative to diazepam in substance abusers dependent on benzodiazepines due to its decreased abuse potential. In individuals dependent on benzodiazepines who have been using benzodiazepines long-term, taper regimens of 6-12 months have been recommended and found to be more successful. More rapid detoxifications e.g. of a month are not recommended as they lead to more severe withdrawal symptoms.

Tolerance leads to a reduction in GABA receptors and function; when benzodiazepines are reduced or stopped this leads to an unmasking of these compensatory changes in the nervous system with the appearance of physical and mental withdrawal effects such as anxiety, insomnia, autonomic hyperactivity and possibly seizures.

Common Withdrawal Symptoms

Include the following:

• Depression.
• Shaking.
• Feeling unreal.
• Appetite loss.
• Muscle twitching.
• Memory loss.
• Motor impairment.
• Nausea.
• Muscle pains.
• Dizziness.
• Apparent movement of still objects.
• Feeling faint.
• Noise sensitivity.
• Light sensitivity.
• Peculiar taste.
• Pins and needles.
• Touch sensitivity.
• Sore eyes.
• Hallucinations.
• Smell sensitivity.

All sedative-hypnotics, e.g. alcohol, barbiturates, benzodiazepines and Z-drugs have a similar mechanism of action, working on the GABAA receptor complex and are cross tolerant with each other and also have abuse potential. Use of prescription sedative-hypnotics – for example, the nonbenzodiazepine Z-drugs – often leads to a relapse back into substance misuse with one author stating this occurs in over a quarter of those who have achieved abstinence.

Background

Benzodiazepines are a commonly abused class of drugs, although there is debate as to whether certain benzodiazepines have higher abuse potential than others. In animal and human studies the abuse potential of benzodiazepines is classed as moderate in comparison to other drugs of abuse. Benzodiazepines are commonly abused by poly drug users, especially heroin addicts, alcoholics or amphetamine addicts when “coming down”. but sometimes are misused in isolation as the primary drug of misuse. They can be misused to achieve the high that benzodiazepines produce or more commonly they are used to either enhance the effects of other CNS depressant drugs, to stave off withdrawal effects of other drugs or combat the effects of stimulants. As many as 30-50% of alcoholics are also benzodiazepine misusers. Drug abusers often abuse high doses which makes serious benzodiazepine withdrawal symptoms such as psychosis or convulsions more likely to occur during withdrawal.

Benzodiazepine abuse increases risk-taking behaviours such as unprotected sex and sharing of needles amongst intravenous abusers of benzodiazepines. Abuse is also associated with blackouts, memory loss, aggression, violence, and chaotic behaviour associated with paranoia. There is little support for long-term maintenance of benzodiazepine abusers and thus a withdrawal regime is indicated when benzodiazepine abuse becomes a dependence. The main source of illicit benzodiazepines are diverted benzodiazepines obtained originally on prescription; other sources include thefts from pharmacies and pharmaceutical warehouses. Benzodiazepine abuse is steadily increasing and is now a major public health problem. Benzodiazepine abuse is mostly limited to individuals who abuse other drugs, i.e. poly-drug abusers. Most prescribed users do not abuse their medication, however, some high dose prescribed users do become involved with the illicit drug scene. Abuse of benzodiazepines occurs in a wide age range of people and includes teenagers and the old. The abuse potential or drug-liking effects appears to be dose related, with low doses of benzodiazepines having limited drug liking effects but higher doses increasing the abuse potential/drug-liking properties.

Health-Related Complications

Refer to Long-Term Effects of Benzodiazepine Use.

Complications of benzodiazepine abuse include drug-related deaths due to overdose especially in combination with other depressant drugs such as opioids. Other complications include: blackouts and memory loss, paranoia, violence and criminal behaviour, risk-taking sexual behaviour, foetal and neonatal risks if taken in pregnancy, dependence, withdrawal seizures and psychosis. Injection of the drug carries risk of: thrombophlebitis, deep vein thrombosis, deep and superficial abscesses, pulmonary microembolism, rhabdomyolysis, tissue necrosis, gangrene requiring amputation, hepatitis B and C, as well as blood borne infections such as HIV infection (caused by sharing injecting equipment). Long-term use of benzodiazepines can worsen pre-existing depression and anxiety and may potentially also cause dementia with impairments in recent and remote memory functions.

Use is widespread among amphetamine users, with those that use amphetamines and benzodiazepines having greater levels of mental health problems and social deterioration. Benzodiazepine injectors are almost four times more likely to inject using a shared needle than non-benzodiazepine-using injectors. It has been concluded in various studies that benzodiazepine use causes greater levels of risk and psycho-social dysfunction among drug misusers. Poly-drug users who also use benzodiazepines appear to engage in more frequent high-risk behaviours. Those who use stimulant and depressant drugs are more likely to report adverse reactions from stimulant use, more likely to be injecting stimulants and more likely to have been treated for a drug problem than those using stimulant but not depressant drugs.

Risk Factors

Individuals with a substance abuse history are at an increased risk of misusing benzodiazepines.

Several (primary research) studies, even into the last decade, claimed, that individuals with a history of familial abuse of alcohol or who are siblings or children of alcoholics appeared to respond differently to benzodiazepines than so called genetically healthy persons, with males experiencing increased euphoric effects and females having exaggerated responses to the adverse effects of benzodiazepines.

Whilst all benzodiazepines have abuse potential, certain characteristics increase the potential of particular benzodiazepines for abuse. These characteristics are chiefly practical ones – most especially, availability (often based on popular perception of ‘dangerous’ versus ‘non-dangerous’ drugs) through prescribing physicians or illicit distributors. Pharmacological and pharmacokinetic factors are also crucial in determining abuse potentials. A short elimination half-life, high potency and a rapid onset of action are characteristics which increase the abuse potential of benzodiazepines. The following table provides the elimination half-life, approximate equivalent doses, speed of onset of action, and duration of behavioural effects.

Refer to Benzodiazepine Overdose.

Epidemiology

Little attention has focused on the degree that benzodiazepines are abused as a primary drug of choice, but they are frequently abused alongside other drugs of abuse, especially alcohol, stimulants and opiates. The benzodiazepine most commonly abused can vary from country to country and depends on factors including local popularity as well as which benzodiazepines are available. Nitrazepam for example is commonly abused in Nepal and the United Kingdom, whereas in the United States of America where nitrazepam is not available on prescription other benzodiazepines are more commonly abused. In the United Kingdom and Australia there have been epidemics of temazepam abuse. Particular problems with abuse of temazepam are often related to gel capsules being melted and injected and drug-related deaths. Injecting most benzodiazepines is dangerous because of their relative insolubility in water (with the exception of midazolam), leading to potentially serious adverse health consequences for users.

Benzodiazepines are a commonly misused class of drug. A study in Sweden found that benzodiazepines are the most common drug class of forged prescriptions in Sweden. Concentrations of benzodiazepines detected in impaired motor vehicle drivers often exceeding therapeutic doses have been reported in Sweden and in Northern Ireland. One of the hallmarks of problematic benzodiazepine drug misuse is escalation of dose. Most licit prescribed users of benzodiazepines do not escalate their dose of benzodiazepines.

Society and Culture

Drug-Related Crime

Problem benzodiazepine use can be associated with various deviant behaviours, including drug-related crime. In a survey of police detainees carried out by the Australian Government, both legal and illegal users of benzodiazepines were found to be more likely to have lived on the streets, less likely to have been in full-time work and more likely to have used heroin or methamphetamines in the past 30 days from the date of taking part in the survey. Benzodiazepine users were also more likely to be receiving illegal incomes and more likely to have been arrested or imprisoned in the previous year. Benzodiazepines were sometimes reported to be used alone, but most often formed part of a poly drug-using problem. Female users were more likely than men to be using heroin, whereas male users were more likely to report amphetamine use. Benzodiazepine users were more likely than non-users to claim government financial benefits and benzodiazepine users who were also poly-drug users were the most likely to be claiming government financial benefits. Those who reported using benzodiazepines alone were found to be in the mid-range when compared to other drug using patterns in terms of property crimes and criminal breaches. Of the detainees reporting benzodiazepine use, one in five reported injection use, mostly of illicit temazepam, with some who reported injecting prescribed benzodiazepines. The injection was a concern in this survey due to increased health risks. The main problems highlighted in this survey were concerns of dependence, the potential for overdose of benzodiazepines in combination with opiates and the health problems associated with injection of benzodiazepines.

Benzodiazepines are also sometimes used for drug facilitated sexual assaults and robbery, however, alcohol remains the most common drug involved in drug facilitated assaults. The muscle relaxant, disinhibiting and amnesia producing effects of benzodiazepines are the pharmacological properties which make these drugs effective in drug-facilitated crimes. Serial killer Jeffrey Dahmer admitted to using triazolam (Halcion), and occasionally temazepam (Restoril), in order to sedate his victims prior to murdering them.

In a 2017 publication, an analysis of the blood samples of 22 victims of drug-facilitated robberies in Bangladesh revealed that criminals use different mixtures of Benzodiazepines including Lorazepam, Midazolam, Diazepam and Nordiazepam to immobilise and then rob their victims.

Drug Regulation and Enforcement

Europe

Temazepam abuse and seizures have been falling in the UK probably due to its reclassification as Schedule 3 controlled drug with tighter prescribing restrictions and the resultant reduction in availability. A total of 2.75 million temazepam capsules were seized in the Netherlands by authorities between 1996 and 1999. In Northern Ireland statistics of individuals attending drug addiction treatment centres found that benzodiazepines were the 2nd most commonly reported main problem drugs (31% of attendees). Cannabis was the top with 35% of individuals reporting it as their main problem drug. The statistics showed that treatment for benzodiazepines as the main problematic drug had more than doubled from the previous year and was a growing problem in Northern Ireland.

Oceania

Benzodiazepines are common drugs of abuse in Australia and New Zealand, particularly among those who may also be using other illicit drugs. The intravenous use of temazepam poses the greatest threat to those who misuse benzodiazepines. Simultaneous consumption of temazepam with heroin is a potential risk factor of overdose. An Australian study of non-fatal heroin overdoses noted that 26% of heroin users had consumed temazepam at the time of their overdose. This is consistent with an NSW investigation of coronial files from 1992. Temazepam was found in 26% of heroin-related deaths. Temazepam, including tablet formulations, are used intravenously. In an Australian study of 210 heroin users who used temazepam, 48% had injected it. Although abuse of benzodiazepines has decreased over the past few years, temazepam continues to be a major drug of abuse in Australia. In certain states like Victoria and Queensland, temazepam accounts for most benzodiazepine sought by forgery of prescriptions and through pharmacy burglary. Darke, Ross & Hall found that different benzodiazepines have different abuse potential. The more rapid the increase in the plasma level following ingestion, the greater the intoxicating effect and the more open to abuse the drug becomes. The speed of onset of action of a particular benzodiazepine correlates well with the ‘popularity’ of that drug for abuse. The two most common reasons for preference for a benzodiazepine were that it was the ‘strongest’ and that it gave a good ‘high’.

North America

The most frequently abused of the benzodiazepines in both the United States and Canada are alprazolam, clonazepam, lorazepam and diazepam.

East and Southeast Asia

The Central Narcotics Bureau of Singapore seized 94,200 nimetazepam tablets in 2003. This is the largest nimetazepam seizure recorded since nimetazepam became a controlled drug under the Misuse of Drugs Act in 1992. In Singapore nimetazepam is a Class C controlled drug.

In Hong Kong abuse of prescription medicinal preparations continued in 2006 and seizures of midazolam (120,611 tablets), nimetazepam/nitrazepam (17,457 tablets), triazolam (1,071 tablets), diazepam (48,923 tablets) and chlordiazepoxide (5,853 tablets) were made. Heroin addicts used such tablets (crushed and mixed with heroin) to prolong the effect of the narcotic and ease withdrawal symptoms.