Author: Andrew Marshall

Founder & Editor of the BootCampMilitaryFitnessInstitute.com, MilitaryGogglebox.com, and Mental-Health-Matters.org.

What is Drug Delivery?

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Introduction

Drug delivery refers to approaches, formulations, manufacturing techniques, storage systems, and technologies involved in transporting a pharmaceutical compound to its target site to achieve a desired therapeutic effect.

Principles related to drug preparation, route of administration, site-specific targeting, metabolism, and toxicity are used to optimise efficacy and safety, and to improve patient convenience and compliance. Drug delivery is aimed at altering a drug’s pharmacokinetics and specificity by formulating it with different excipients, drug carriers, and medical devices. There is additional emphasis on increasing the bioavailability and duration of action of a drug to improve therapeutic outcomes. Some research has also been focused on improving safety for the person administering the medication. For example, several types of microneedle patches have been developed for administering vaccines and other medications to reduce the risk of needlestick injury.

Drug delivery is a concept heavily integrated with dosage form and route of administration, the latter sometimes being considered part of the definition. While route of administration is often used interchangeably with drug delivery, the two are separate concepts. Route of administration refers to the path a drug takes to enter the body, whereas drug delivery also encompasses the engineering of delivery systems and can include different dose forms and devices used to deliver a drug through the same route. Common routes of administration include oral, parenteral (injected), sublingual, topical, transdermal, inhaled, rectal, and vaginal, however drug delivery is not limited to these routes and there may be several ways to deliver medications through each route.

Since the approval of the first controlled-release formulation in the 1950s, research into new delivery systems has been progressing, as opposed to new drug development which has been declining. Several factors may be contributing to this shift in focus. One of the driving factors is the high cost of developing new drugs. A 2013 review found the cost of developing a delivery system was only 10% of the cost of developing a new pharmaceutical. A more recent study found the median cost of bringing a new drug to market was $985 million in 2020, but did not look at the cost of developing drug delivery systems. Other factors that have potentially influenced the increase in drug delivery system development may include the increasing prevalence of both chronic and infectious diseases, as well as a general increased understanding of the pharmacology, pharmacokinetics, and pharmacodynamics of many drugs.

Current Efforts

Current efforts in drug delivery are vast and include topics such as:

Targeted Delivery

Targeted drug delivery is the delivery of a drug to its target site without having an effect on other tissues. Interest in targeted drug delivery has grown drastically due to its potential implications in the treatment of cancers and other chronic diseases. In order to achieve efficient targeted delivery, the designed system must avoid the host’s defence mechanisms and circulate to its intended site of action. A number of drug carriers have been studied to effectively target specific tissues, including liposomes, nanogels, and other nanotechnologies.

Controlled-release Formulations

Controlled or modified-release formulations alter the rate and timing at which a drug is liberated, in order to produce adequate or sustained drug concentrations. The first controlled-release (CR) formulation that was developed was Dexedrine in the 1950s. This period of time saw more drugs being formulated as CR, as well as the introduction of transdermal patches to allow drugs to slowly absorb through the skin. Since then, countless other CR products have been developed to account for the physiochemical properties of different drugs, such as depot injections for antipsychotics and sex hormones that require dosing once every few months.

Since the late 1990s, most of the research around CR formulations has been focused on implementing nanoparticles to decrease the rate of drug clearance.

Delivery of Biologic Drugs

Pharmaceutical preparations containing peptides, proteins, antibodies, genes, or other biologic components often face absorption issues due to their large sizes or electrostatic charges, and may be susceptible to enzymatic degradation once they have entered the body. For these reasons, recent efforts in drug delivery have been focused on methods to avoid these issues through the use of liposomes, nanoparticles, fusion proteins, protein-cage nanoparticles and many others. Intracellular delivery of macromolecules by chemical carriers is most advanced for RNA, as known from RNA-based COVID-19 vaccines, while proteins have also been delivered into cells in vivo and DNA is routinely delivered in vitro.

On This Day … 14 November [2022]

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People (Deaths)

  • 2008 – Robert E. Valett, American psychologist, teacher, and author (b. 1927).

Robert E. Valett

Robert E. Valett (22 November 1927 to 14 November 2008) was an American psychology professor who wrote more than 20 books primarily focused on educational psychology.

He earned the distinguished psychologist award from the San Joaquin Psychological Association and was a president of the California Association of School Psychologists.

On This Day … 12 November [2022]

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People (Deaths)

  • 2012 – Daniel Stern, American psychologist and theorist (b. 1934).

Daniel Stern

Daniel N. Stern (16 August 1934 to 12 November 2012) was a prominent American developmental psychologist and psychoanalyst, specialising in infant development, on which he had written a number of books – most notably The Interpersonal World of the Infant (1985).

Stern’s 1985 and 1995 research and conceptualisation created a bridge between psychoanalysis and research-based developmental models.

What is Liberation (in Pharmacology)?

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Introduction

Liberation is the first step in the process by which medication enters the body and liberates the active ingredient that has been administered. The pharmaceutical drug must separate from the vehicle or the excipient that it was mixed with during manufacture. Some authors split the process of liberation into three steps: disintegration, disaggregation and dissolution. A limiting factor in the adsorption of pharmaceutical drugs is the degree to which they are ionised, as cell membranes are relatively impermeable to ionised molecules.

The characteristics of a medication’s excipient play a fundamental role in creating a suitable environment for the correct absorption of a drug. This can mean that the same dose of a drug in different forms can have different bioequivalence, as they yield different plasma concentrations and therefore have different therapeutic effects. Dosage forms with modified release (such as delayed or extended release) allow this difference to be usefully applied.

Dissolution

In a typical situation, a pill taken orally will pass through the oesophagus and into the stomach. As the stomach has an aqueous environment, it is the first place where the pill can dissolve. The rate of dissolution is a key element in controlling the duration of a drug’s effect. For this reason, different forms of the same medication can have the same active ingredients but different dissolution rates. If a drug is administered in a form that is not rapidly dissolved, the drug will be absorbed more gradually over time and its action will have a longer duration. A consequence of this is that patients will comply more closely to a prescribed course of treatment, if the medication does not have to be taken as frequently. In addition, a slow release system will maintain drug concentrations within a therapeutically acceptable range for longer than quicker releasing delivery systems as these result in more pronounced peaks in plasma concentration.

The dissolution rate is described by the Noyes-Whitney equation:

Where:

  • {\frac {dW}{dt}} is the dissolution rate.
  • A is the solid’s surface area.
  • C is the concentration of the solid in the bulk dissolution medium.
  • C8 is the concentration of the solid in the diffusion layer surrounding the solid.
  • D is the diffusion coefficient.
  • L is the thickness of the diffusion layer.

As the solution is already in a dissolved state, it does not have to go through a dissolution stage before absorption begins.

Ionisation

Cell membranes present a greater barrier to the movement of ionised molecules than non-ionised liposoluble substances. This is particularly important for substances that are weakly amphoteric. The stomach’s acidic pH and the subsequent alkalization in the intestine modifies the degree of ionisation of acids and weak bases depending on a substance’s pKa. The pKa is the pH at which a substance is present at an equilibrium between ionised and non-ionised molecules. The Henderson-Hasselbalch equation is used to calculate pKa.

This page is based on the copyrighted Wikipedia article < https://en.wikipedia.org/wiki/Liberation_(pharmacology) >; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA.

On This Day … 11 November [2022]

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People (Deaths)

  • 2002 – Frances Ames, South African neurologist, psychiatrist, and human rights activist (b. 1920).

Frances Ames

Frances Rix Ames (20 April 1920 to 11 November 2002) was a South African neurologist, psychiatrist, and human rights activist, best known for leading the medical ethics inquiry into the death of anti-apartheid activist Steve Biko, who died from medical neglect after being tortured in police custody. When the South African Medical and Dental Council (SAMDC) declined to discipline the chief district surgeon and his assistant who treated Biko, Ames and a group of five academics and physicians raised funds and fought an eight-year legal battle against the medical establishment. Ames risked her personal safety and academic career in her pursuit of justice, taking the dispute to the South African Supreme Court, where she eventually won the case in 1985.

Born in Pretoria and raised in poverty in Cape Town, Ames became the first woman to receive a Doctor of Medicine degree from the University of Cape Town in 1964. Ames studied the effects of cannabis on the brain and published several articles on the subject. Seeing the therapeutic benefits of cannabis on patients in her own hospital, she became an early proponent of legalization for medicinal use. She headed the neurology department at Groote Schuur Hospital before retiring in 1985, but continued to lecture at Valkenberg and Alexandra Hospital. After apartheid was dismantled in 1994, Ames testified at the Truth and Reconciliation Commission about her work on the “Biko doctors” medical ethics inquiry. In 1999, Nelson Mandela awarded Ames the Star of South Africa, the country’s highest civilian award, in recognition of her work on behalf of human rights.

What is a Dosage Form?

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Introduction

Dosage forms (also called unit doses) are pharmaceutical drug products in the form in which they are marketed for use, with a specific mixture of active ingredients and inactive components (excipients), in a particular configuration (such as a capsule shell, for example), and apportioned into a particular dose. For example, two products may both be amoxicillin, but one is in 500 mg capsules and another is in 250 mg chewable tablets.

The term unit dose can also sometimes encompass non-reusable packaging as well (especially when each drug product is individually packaged), although the US Food and Drug Administration (FDA) distinguishes that by unit-dose “packaging” or “dispensing”. Depending on the context, multi(ple) unit dose can refer to distinct drug products packaged together, or to a single drug product containing multiple drugs and/or doses. The term dosage form can also sometimes refer only to the pharmaceutical formulation of a drug product’s constituent drug substance(s) and any blends involved, without considering matters beyond that (like how it is ultimately configured as a consumable product such as a capsule, patch, etc.). Because of the somewhat vague boundaries and unclear overlap of these terms and certain variants and qualifiers within the pharmaceutical industry, caution is often advisable when conversing with someone who may be unfamiliar with another person’s use of the term.

Depending on the method/route of administration, dosage forms come in several types. These include many kinds of liquid, solid, and semisolid dosage forms. Common dosage forms include pill, tablet, or capsule, drink or syrup, among many others. In naturopathy, dosages can take the form of decoctions and herbal teas, as well as the more conventional methods previously mentioned. A liquid dosage form is the liquid form of a dose of a chemical compound used as a drug or medication intended for administration or consumption.

The route of administration (ROA) for drug delivery is dependent on the dosage form of the substance in question. Various dosage forms may exist for a single particular drug, since some medical conditions such as being unconscious can restrict ROA. For example, persistent nausea, especially with vomiting, may make it difficult to use an oral dosage form, and in such a case, it may be necessary to use an alternative route such as inhalational, buccal, sublingual, nasal, suppository or parenteral instead. Additionally, a specific dosage form may be a requirement for certain kinds of drugs, as there may be issues with various factors like chemical stability or pharmacokinetics. As an example, insulin cannot be given orally because upon being administered in this manner, it is extensively metabolized in the gastrointestinal tract (GIT) before reaching the blood stream, and is thereby incapable of sufficiently reaching its therapeutic target destinations. The oral and intravenous doses of a drug such as paracetamol will differ for the same reason.

Oral

  • Pills, i.e. tablets or capsules.
  • Liquids such as syrups, solutions, elixers, emulsions, and tinctures.
  • Liquids such as decoctions and herbal teas.
  • Orally disintegrating tablets.
  • Lozenges or candy (electuaries).
  • Thin films (e.g. Listerine Pocketpaks, nitroglycerin) to be placed on top of or underneath the tongue as well as against the cheek.
  • Powders or effervescent powder or tablets, often instructed to be mixed into a food item.
  • Plants or seeds prepared in various ways such as a cannabis edible.
  • Pastes such as high fluoride toothpastes.
  • Gases such as oxygen (can also be delivered through the nose).

Ophthalmic

  • Eye drops.
  • Lotions.
  • Ointments.
  • Emulsions.

Inhalation

  • Aerosolised medication.
  • Dry-powder Inhalers or metered dose inhalers.
  • Nebuliser-administered medication.
  • Smoking.
  • Vaporiser-administered medication.

Unintended Ingredients

Talc is an excipient often used in pharmaceutical tablets that may end up being crushed to a powder against medical advice or for recreational use. Also, illicit drugs that occur as white powder in their pure form are often cut with cheap talc. Natural talc is cheap but contains asbestos while asbestos-free talc is more expensive. Inhaled talc that has asbestos is generally accepted as being able to cause lung cancer if it is inhaled. The evidence about asbestos-free talc is less clear, according to the American Cancer Society.

Injection

  • Parenteral.
  • Intradermally-administered (ID).
  • Subcutaneously-administered (SC).
  • Intramuscularly-administered (IM).
  • Intraosseous administration (IO).
  • Intraperitoneally-administered (IP).
  • intravenously-administered (IV).
  • Intracavernously-administered (ICI).

These are usually solutions and suspensions.

Unintended Ingredients

Safe

Eye drops (normal saline in disposable packages) are distributed to syringe users by needle exchange programs.

Unsafe

The injection of talc from crushed pills has been associated with pulmonary talcosis in intravenous drug users.

Topical

  • Creams, liniments, balms (such as lip balm or antiperspirants and deodorants), lotions, or ointments, etc.
  • Gels and hydrogels.
  • Ear drops.
  • Transdermal and dermal patches to be applied to the skin.
  • Powders.

Unintended Use

  • It is not safe to calculate divided doses by cutting and weighing medical skin patches, because there’s no guarantee that the substance is evenly distributed on the patch surface. For example, fentanyl transdermal patches are designed to slowly release the substance over 3 days. It is well known that cut fentanyl transdermal consumed orally have cause overdoses and deaths.
  • Single blotting papers for illicit drugs injected from solvents in syringes may also cause uneven distribution across the surface.

Other

  • Intravaginal administration:
    • Vaginal rings.
    • Capsules and tablets.
    • Suppositories.
  • Rectal administration (enteral):
    • Suppositories.
    • Suspensions and solutions in the form of enemas.
    • Gels.
  • Urethral.
  • Nasal sprays.

This page is based on the copyrighted Wikipedia article < https://en.wikipedia.org/wiki/Dosage_form >; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA.

What is a Dose (Biochemistry)?

Published on by Andrew Marshall1 Comment

Introduction

A dose is a measured quantity of a medicine, nutrient, or pathogen which is delivered as a unit. The greater the quantity delivered, the larger the dose. Doses are most commonly measured for compounds in medicine. The term is usually applied to the quantity of a drug or other agent administered for therapeutic purposes, but may be used to describe any case where a substance is introduced to the body. In nutrition, the term is usually applied to how much of a specific nutrient is in a person’s diet or in a particular food, meal, or dietary supplement. For bacterial or viral agents, dose typically refers to the amount of the pathogen required to infect a host.

In clinical pharmacology, dose refers to dosage or amount of dose administered to a person, whereas exposure means the time-dependent concentration (often in the circulatory blood or plasma) or concentration-derived parameters such as AUC (area under the concentration curve) and Cmax (peak level of the concentration curve) of the drug after its administrationneeded]. This is in contrast to their interchangeable use in other fields.

Refer to Defined Daily Dose, Prescribed Baily Dose, Maintenance Dose, and Dosage Form.

Factors Affecting Dose

A ‘dose’ of any chemical or biological agent (active ingredient) has several factors which are critical to its effectiveness. The first is concentration, that is, how much of the agent is being administered to the body at once.

Another factor is the duration of exposure. Some drugs or supplements have a slow-release feature in which portions of the medication are metabolized at different times, which changes the impacts the active ingredients have on the body. Some substances are meant to be taken in small doses over large periods of time to maintain a constant level in the body, while others are meant to have a large impact once and be expelled from the body after its work is done. It’s entirely dependent on the function of the drug or supplement.

The route of administration is important as well. Whether a drug is ingested orally, injected into a muscle or vein, absorbed through a mucous membrane, or any of the other types of administration routes, affects how quickly the substance will be metabolized by the body and thus effects the concentration of the active ingredient(s). Dose-response curves may illustrate the relationship of these metabolic effects.

Medicines

Over-the-Counter Medications

In over-the-counter medicines, dosage is based on age. Typically, different doses are recommended for children 6 years and under, children aged 6 to 12 years, and persons 12 years and older, but outside of those ranges the guidance is slim. This can lead to serial under or overdosing, as smaller people take more than they should and larger people take less. Over-the-counter medications are typically accompanied by a set of instructions directing the patient to take a certain small dose, followed by another small dose if their symptoms don’t subside. Under-dosing is a common problem in pharmacy, as predicting an average dose that is effective for all individuals is extremely challenging because body weight and size impacts how the dose acts within the body.

Prescription Drugs

Prescription drug dosage is based typically on body weight. Drugs come with a recommended dose in milligrams or micrograms per kilogram of body weight, and that is used in conjunction with the patient’s body weight to determine a safe dosage. In single dosage scenarios, the patient’s body weight and the drug’s recommended dose per kilogram are used to determine a safe one-time dose. In drugs where multiple doses of treatment are needed in a day, the physician must take into account information regarding the total amount of the drug which is safe to use in one day, and how that should be broken up into intervals for the most effective treatment for the patient. Medication underdosing occurs commonly when physicians write prescriptions for a dosage that is correct for a certain time, but fails to increase the dosage as the patient needs (i.e. weight based dosing in children, or increasing dosages of chemotherapy drugs if a patient’s condition worsens).

Medical Cannabis

Medical cannabis is used to treat the symptoms of a wide variety of diseases and conditions. The dose of cannabis depends on the individual, the condition being treated, and the ratio of cannabidiol (CBD) to tetrahydrocannabinol (THC) in the cannabis. CBD is a chemical component of cannabis that is not intoxicating and used to treat conditions like epilepsy and other neuropsychiatric disorders. THC is a chemical component of cannabis that is psychoactive. It has been used to treat nausea and discomfort in cancer patients receiving chemotherapy treatment. For anxiety, depression, and other mental health ailments, a CBD to THC ratio of 10 to 1 is recommended. For cancer and neurological conditions, a CBD to THC ratio of 1 to 1 is recommended. The correct dosage for a patient is dependent on their individual reaction to both chemicals, and therefore the dosing must be continually adjusted once treatment is initiated to find the right balance.

There is limited consensus throughout the scientific community regarding the effectiveness of medicinal cannabis.

Cancer

Calculating drug dosages for treatment for more serious diseases like cancer is commonly done through measuring the patient’s body surface area. There are approximately 25 different formulae for measuring a patient’s body surface area, none of them exact. Studies show that selecting the best method for an individual patient is a difficult task; consequently, patient often receive too much or too little medication due to their particular physical anomalies. Therefore, these formulas are typically adjusted by what is known as ‘toxicity-adjusting dosing,’ whereby physicians monitor immune suppression and adjust dosing accordingly. Because this strategy of trial and error requires close monitoring, it is inefficient, risky, and cost ineffective. Research into the development of safer and more accurate dosing methods is ongoing.

Ongoing Research

Another approach that’s been investigated recently is dosing on a molecular level, either through conventional delivery systems, nanoparticle delivery, light-triggered delivery, or other less known/used methods. By combining these drugs with a system that detects the concentration of drug particles in the blood, proper dosing could be achieved for each individual patient. Research in this field was initiated with monitoring of small-molecule cocaine levels in undiluted blood serum with electrochemical aptamer-based sensing. DNA aptamers, which are peptides that have with specific target molecules that they search for, fold in response to the molecule when they find it, and this technology was used in a microfluidic detection system to create an electrochemical signal that physicians can read. Researchers tested it on cocaine detection and found that it successfully found trace amounts of cocaine in blood.

This research was expanded upon and led to the creation of a product called MEDIC (microfluidic electrochemical detector for in vivo continuous monitoring) developed by faculty at the University of California at Santa Barbara. MEDIC is an instrument that can continuously determine the concentrations of different molecules in the blood. The blood does not have to be mixed with anything prior to testing to create a ‘serum’ as the first device did. MEDIC can detect a wide variety of drug molecules and biomarkers. In trials, early models of the device failed after about half an hour because the proteins in whole blood clung to the sensors and clogged the components. This problem was solved via a second chamber that allowed a liquid buffer to flow over the sensors with the blood, without mixing or disturbing the blood, so the results remained unchanged. The device is still in clinical trials and actual implementation in medicine is likely years away, however in the interim, its creators estimate that it could also be used in the pharmaceutical industry to allow for better testing in Phase 3 clinical trials.

Vaccines

Vaccinations are typically administered as liquids and dosed in millilitres. Each individual vaccine comes with constraints regarding at what age they should be administered, how many doses must be given, and over what period of time. There are 15 vaccines that the Centres for Disease Control and Prevention recommend every person (in the United States and Canada) receive between birth and 18 years of age to protect against various infectious agents that may affect long-term health. Most vaccines require multiple doses for full immunity, given in recommended intervals depending on the vaccine. There are several typical vaccination routes:

  • Intramuscular: the needle is inserted perpendicular to the skin into the muscle, beneath the skin and (subcutaneous) tissues that rest on top.
  • Subcutaneous: the needle is inserted at a 45-degree angle into the (subcutaneous) tissue between the outer layer of the skin and the muscle.
  • Intranasal: the vaccine is sprayed into the nose and absorbed through the nasal passage.
  • Oral: the vaccine is swallowed and ingested.

Nutrition

For healthy humans, experts recommend daily intake quantities of certain vitamins and minerals. The Food and Nutrition Board, Institute of Medicine, and National Academy of Sciences sets a recommended Dietary Reference Intake (DRI) in several forms:

  • Recommended Dietary Allowance (RDA): average daily intake which adequately meets the nutrient requirements of 97-98% of healthy individuals.
  • Adequate Intake (AI): established when the evidence gathered for an RDA is inconclusive, An AI is assumed to recommend a daily amount to meet nutritional adequacy.
  • Tolerable Upper Intake Level (UL): maximum amount of a nutrient which can be consumed without causing adverse impacts to an individual’s health.

DRIs are established for elements, vitamins, and macronutrients. Common elemental and vitamin dosages are milligrams per day (mg/d) or micrograms per day (μg/d). Common macronutrient dosages are in grams per day (g/d). Dosages for all three are established by both gender and age.

Individuals take vitamin and mineral supplements to promote healthier lifestyles and prevent development of chronic diseases. There is no conclusive evidence linking continued vitamin and mineral supplement intake with longevity of life.

Infectious Dose

The infectious dose of a pathogen is the number of cells required to infect the host. All pathogens have an infectious dose typically given in number of cells. The infectious dose varies by organism and can be dependent on the specific type of strain. Some pathogens can infect a host with only a few cells, while others require millions or billions.

Examples of infectious doses, ranked loosely in increasing order:

  • Enterohemorrhagic E. coli (causes haemorrhaging of the intestines): 10 bacteria cells.
  • Hepatitis A: 10-100 virus particles.
  • Norovirus (commonly called ‘a stomach bug’): 10-100 virus particles.
  • Rotavirus (severe diarrhoea, can be fatal): 10-100 virus particles.
  • Shigella (shigellosis): 500 bacteria cells.
  • Streptococcus pyogenes (Group A strep throat): 1000 bacteria cells.
  • Salmonella: varies by strain, 100-1 billion bacteria cells.
  • Vibrio cholerae (Cholera): 1000-100,000,000 bacteria cells.

Typically, stomach acids can kill bacteria below the infectious dosing range for a given pathogen and keep the host from feeling symptoms or falling ill. Complexes constructed by fat can protect infectious agents from stomach acid, making fatty foods more likely to contain pathogens that successfully infect the host. For individuals with low or reduced stomach acid concentrations, in infectious dosage for a pathogen will be lower than normal.

Rather than being administered by a physician or individual, infectious dosages are transmitted to a person from other persons or the environment, are generally accidental, and result in adverse side effects until the pathogen is defeated by the individual’s immune system or flushed out of the individual’s system by excretory processes.

This page is based on the copyrighted Wikipedia article < https://en.wikipedia.org/wiki/Dose_(biochemistry) >; it is used under the Creative Commons Attribution-ShareAlike 3.0 Unported License (CC-BY-SA). You may redistribute it, verbatim or modified, providing that you comply with the terms of the CC-BY-SA.

On This Day … 09 November [2022]

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People (Births)

  • 1939 – Paul Cameron, American psychologist and academic.
  • 2002 – William Schutz, American psychologist and academic (b. 1925).

Paul Cameron

Paul Drummond Cameron (born 09 November 1939) is an American psychologist. Cameron has been designated by the Southern Poverty Law Center as an anti-gay extremist. While employed at various institutions, including the University of Nebraska, he conducted research on passive smoking, but he is best known today for his claims about homosexuality. After a successful 1982 campaign against a gay rights proposal in Lincoln, Nebraska, he established the Institute for the Scientific Investigation of Sexuality (ISIS), now known as the Family Research Institute (FRI). As FRI’s chairman, Cameron has written contentious papers asserting unproven associations between homosexuality and the perpetration of child sexual abuse and reduced life expectancy. These have been heavily criticised and frequently discredited by others in the field.

In 1983, the American Psychological Association expelled Cameron for non-cooperation with an ethics investigation. Position statements issued by the American Sociological Association, Canadian Psychological Association, and the Nebraska Psychological Association accuse Cameron of misrepresenting social science research.

William Schutz

William Schutz (19 December 1925 to 09 November 2002) was an American psychologist.

In 1958, Schutz introduced a theory of interpersonal relations he called Fundamental Interpersonal Relations Orientation (FIRO). According to the theory three dimensions of interpersonal relations were deemed to be necessary and sufficient to explain most human interaction: Inclusion, Control and Affection. These dimensions have been used to assess group dynamics.

Schutz also created FIRO-B, a measurement instrument with scales that assess the behavioural aspects of the three dimensions. His advancement of FIRO Theory beyond the FIRO-B tool was most obvious in the change of the “Affection” scale to the “Openness” scale in the “FIRO Element-B”. This change highlighted his newer theory that behaviour comes from feelings (“FIRO Element-F”) and the self-concept (“FIRO Element-S”). “Underlying the behavior of openness is the feeling of being likable or unlikeable, lovable or unlovable. I find you likable if I like myself in your presence, if you create an atmosphere within which I like myself.”

On This Day … 08 November [2022]

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People (Births)

People (Deaths)

  • 2007 – Chad Varah, English priest, founded The Samaritans (b. 1911).

Hermann Rorschach

Hermann Rorschach (08 November 1884 to 02 April 1922) was a Swiss psychiatrist and psychoanalyst.

His education in art helped to spur the development of a set of inkblots that were used experimentally to measure various unconscious parts of the subject’s personality. His method has come to be referred to as the Rorschach test, iterations of which have continued to be used over the years to help identify personality, psychotic, and neurological disorders. Rorschach continued to refine the test until his premature death at age 37.

Chad Varah

Edward Chad Varah CH CBE (12 November 1911 to 08 November 2007) was a British Anglican priest and social activist from England. In 1953, he founded the Samaritans, the world’s first crisis hotline, to provide telephone support to those contemplating suicide.

The Samaritans

Samaritans is a registered charity aimed at providing emotional support to anyone in emotional distress, struggling to cope or at risk of suicide throughout the United Kingdom and the Republic of Ireland, often through its telephone helpline. Its name derives from the biblical Parable of the Good Samaritan although the organisation itself is not religious.

Its international network exists under the name Befrienders Worldwide, which is part of the Volunteer Emotional Support Helplines (VESH) with Lifeline International and the International Federation of Telephone Emergency Services (IFOTES).

What is a Medical Prescription?

Published on by Andrew Marshall3 Comments

Introduction

A prescription, often abbreviated ℞ or Rx, is a formal communication from a physician or other registered health-care professional to a pharmacist, authorising them to dispense a specific prescription drug for a specific patient.

Historically, it was a physician’s instruction to an apothecary listing the materials to be compounded into a treatment – the symbol ℞ (a capital letter R, crossed to indicate abbreviation) comes from the first word of a medieval prescription, Latin: Recipere (“Take thou”), that gave the list of the materials to be compounded.

Brief History

The idea of prescriptions dates back to the beginning of history. So long as there were medications and a writing system to capture directions for preparation and usage, there were prescriptions.

Modern prescriptions are actually extemporaneous prescriptions (from the Latin ex tempore, “at/from the time”), meaning that the prescription is written on the spot for a specific patient with a specific ailment. This is distinguished from a non-extemporaneous prescription that is a generic recipe for a general ailment. Modern prescriptions evolved with the separation of the role of the pharmacists from that of the physician. Today the term extemporaneous prescriptions is reserved for compound prescriptions that requires the pharmacist to mix or compound the medication in the pharmacy for the specific needs of the patient.

Predating modern legal definitions of a prescription, a prescription traditionally is composed of four parts: a superscription, inscription, subscription, and signature.

The superscription section contains the date of the prescription and patient information (name, address, age, etc.). The symbol “℞” separates the superscription from the inscriptions sections. In this arrangement of the prescription, the “℞” is a symbol for recipe or literally the imperative “take!” This is an exhortation to the pharmacist by the medical practitioner, “I want the patient to have the following medication” – in other words, “take the following components and compound this medication for the patient.”

The inscription section defines what is the medication. The inscription section is further composed of one or more of:

  • A basis or chief ingredient intended to cure (curare).
  • An adjuvant to assist its action and make it cure quickly (cito).
  • A corrective to prevent or lessen any undesirable effect (tuto).
  • A vehicle or excipient to make it suitable for administration and pleasant to the patient (jucunde).

The subscription section contains dispensing directions to the pharmacist. This may be compounding instructions or quantities.

The signature section contains directions to the patient and is often abbreviated “Sig.” or “Signa.” It also obviously contains the signature of the prescribing medical practitioner though the word signature has two distinct meanings here and the abbreviations are sometimes used to avoid confusion.

Thus sample prescriptions in modern textbooks are often presented as:

  • Rx: medication.
  • Disp.: dispensing instructions.
  • Sig.: patient instructions.

Format and Definition

For a communication to be accepted as a legal medical prescription, it needs to be filed by a qualified dentist, advanced practice nurse, physician or veterinarian, for whom the medication prescribed is within their scope of practice to prescribe. This is regardless of whether the prescription includes prescription drugs, controlled substances or over-the-counter treatments.

Prescriptions may be entered into an electronic medical record system and transmitted electronically to a pharmacy. Alternatively, a prescription may be handwritten on pre-printed prescription forms that have been assembled into pads, or printed onto similar forms using a computer printer or even on plain paper according to the circumstance. In some cases, a prescription may be transmitted from the physician to the pharmacist orally by telephone. The content of a prescription includes the name and address of the prescribing provider and any other legal requirement such as a registration number (e.g. DEA Number in the United States). Unique for each prescription is the name of the patient. In the United Kingdom and Ireland the patient’s name and address must also be recorded. Each prescription is dated and some jurisdictions may place a time limit on the prescription. In the past, prescriptions contained instructions for the pharmacist to use for compounding the pharmaceutical product but most prescriptions now specify pharmaceutical products that were manufactured and require little or no preparation by the pharmacist. Prescriptions also contain directions for the patient to follow when taking the drug. These directions are printed on the label of the pharmaceutical product.

The word “prescription”, from “pre-” (“before”) and “script” (“writing, written”), refers to the fact that the prescription is an order that must be written down before a drug can be dispensed. Those within the industry will often call prescriptions simply “scripts”.

Contents

Every prescription contains who prescribed the prescription, who the prescription is valid for, and what is prescribed. Some jurisdictions, drug types or patient groups require additional information as explained below.

Drug Equivalence and Non-Substitution

Many brand name drugs have cheaper generic drug substitutes that are therapeutically and biochemically equivalent. Prescriptions will also contain instructions on whether the prescriber will allow the pharmacist to substitute a generic version of the drug. This instruction is communicated in a number of ways. In some jurisdictions, the pre-printed prescription contains two signature lines: one line has “dispense as written” printed underneath; the other line has “substitution permitted” underneath. Some have a pre-printed box “dispense as written” for the prescriber to check off (but this is easily checked off by anyone with access to the prescription). In other jurisdictions, the protocol is for the prescriber to handwrite one of the following phrases: “dispense as written”, “DAW”, “brand necessary”, “do not substitute”, “no substitution”, “medically necessary”, “do not interchange”. In Britain’s National Health Service, doctors are reminded that money spent on branded rather than generic drugs is consequently not available for more deserving cases.

Prescriptions for Children

In some jurisdictions, it may be a legal requirement to include the age of child on the prescription. For paediatric prescriptions some advise the inclusion of the age of the child if the patient is less than twelve and the age and months if less than five. In general, including the age on the prescription is helpful, and adding the weight of the child is also helpful.

Label and Instructions

Prescriptions in the USA often have a “label” box. When checked, the pharmacist is instructed to label the medication and provide information about the prescription itself is given in addition to instructions on taking the medication. Otherwise, the patient is simply given the instructions. Some prescribers further inform the patient and pharmacist by providing the indication for the medication; i.e. what is being treated. This assists the pharmacist in checking for errors as many common medications can be used for multiple medical conditions. Some prescriptions will specify whether and how many “repeats” or “refills” are allowed; that is whether the patient may obtain more of the same medication without getting a new prescription from the medical practitioner. Regulations may restrict some types of drugs from being refilled.

Writing Prescriptions

Legal Capacity to Write Prescriptions

National or local (i.e. US state or Canadian provincial) legislation governs who can write a prescription. In the United States, physicians (either M.D., D.O. or D.P.M.) have the broadest prescriptive authority. All 50 US states and the District of Columbia allow licensed certified Physician Assistants (PAs) prescription authority (with some states, limitations exist to controlled substances). All 50 US states and the District of Columbia, Puerto Rico and Guam allow registered certified nurse practitioners and other advanced practice registered nurses (such as certified nurse-midwives) prescription power (with some states including limitations to controlled substances). Many other healthcare professions also have prescriptive authority related to their area of practice. Veterinarians and dentists have prescribing power in all 50 US states and the District of Columbia. Clinical pharmacists are allowed to prescribe in some US states through the use of a drug formulary or collaboration agreements. Florida pharmacists can write prescriptions for a limited set of drugs. In all US states, optometrists prescribe medications to treat certain eye diseases, and also issue spectacle and contact lens prescriptions for corrective eyewear. Several US states have passed RxP legislation, allowing clinical psychologists who are registered as medical psychologists and have also undergone specialised training in script-writing, to prescribe drugs to treat emotional and mental disorders.

In August 2013, legislative changes in the UK allowed physiotherapists and podiatrists to have independent prescribing rights for licensed medicines that are used to treat conditions within their own area of expertise and competence. In 2018 this was extended to paramedics.

Standing Orders

Some jurisdictions allow certain physicians (sometimes a government official like the state Secretary of Health, sometimes physicians in local clinics or pharmacies) to write “standing orders” that act like a prescription for everyone in the general public. These orders also provide a standard procedure for determining if administration is necessary and details of how it is to be performed safely. These are typically used to authorise certain people to perform preventive, low-risk, or emergency care that would be otherwise logistically cumbersome to authorise for individual patients, including vaccinations, prevention of cavities, birth control, treatment of infectious diseases, and reversal of drug overdoses.

Legibility of Handwritten Prescriptions

Doctors’ handwriting is a reference to the stereotypically illegible handwriting of some medical practitioners, which sometimes causes errors in dispensing. In the US, illegible handwriting has been indirectly responsible for at least 7,000 deaths annually.

There are several theories about the causes of this phenomenon. Some sources say the extreme amount of writing doctors employ during training and at work leads to bad handwriting, whereas others claim that doctors neglect proper handwriting due to medical documents being intended to be read solely by medical professionals, not patients. Others simply classify the handwriting of doctors as a handwriting style. The issue may also have a historical origin, as physicians from Europe-influenced schools have historically used Latin words and abbreviations to convey prescriptions; many of the abbreviations are still widely used in the modern day and could be a source of confusion.

Some jurisdictions have legislatively required prescriptions to be legible – Florida, US specifies “legibly printed or typed” – and the Institute for Safe Medication Practices advocated the elimination of handwritten prescriptions altogether. There have been numerous devices designed to electronically read the handwriting of doctors, including electronic character recognition, keyword spotters, and “postprocessing approaches,” though the gradual shift to electronic health records and electronic prescriptions may alleviate the need for handwritten prescriptions altogether. In Britain’s NHS, remaining paper prescriptions are almost invariably computer printed and electronic (rather than paper) communication between surgery and pharmacy is increasingly the norm.

Conventions for Avoiding Ambiguity

Over the years, prescribers have developed many conventions for prescription-writing, with the goal of avoiding ambiguities or misinterpretation. These include:

  • Careful use of decimal points to avoid ambiguity:
    • Avoiding unnecessary decimal points and trailing zeros, e.g. 5 mL rather than 5.0 mL, 0.5 rather than .50 or 0.50, to avoid possible misinterpretation as 50.
    • Always using leading zeros on decimal numbers less than 1: e.g. 0.5 rather than .5 to avoid misinterpretation as 5.
  • Directions written out in full in English (although some common Latin abbreviations are listed below).
  • Quantities given directly or implied by the frequency and duration of the directions.
  • Where the directions are “as needed”, the quantity should always be specified.
  • Where possible, usage directions should specify times (7 am, 3 pm, 11 pm) rather than simply frequency (three times a day) and especially relationship to meals for orally consumed medication.
  • The use of permanent ink.
  • Avoiding units such as “teaspoons” or “tablespoons”.
  • Writing out numbers as words and numerals (“dispense #30 (thirty)”) as in a bank draft or cheque.
  • The use of the apothecaries’ system or avoirdupois units and symbols of measure – pints (O), ounces (℥), drams (ℨ), scruples (℈), grains (gr), and minims (♏︎) – is discouraged given the potential for confusion. For example, the abbreviation for a grain (“gr”) can be confused with the gram, abbreviated g, and the symbol for minims (♏︎), which looks almost identical to an ‘m’, can be confused with micrograms or metres. Also, the symbols for ounce (℥) and dram (ℨ) can easily be confused with the numeral ‘3’, and the symbol for pint (O) can be easily read as a ‘0’. Given the potential for errors, metric equivalents should always be used.
  • The degree symbol (°), which is commonly used as an abbreviation for hours (e.g., “q 2-4°” for every 2-4 hours), should not be used, since it can be confused with a ‘0’ (zero). Further, the use of the degree symbol for primary, secondary, and tertiary (1°, 2°, and 3°) is discouraged, since the former could be confused with quantities (i.e. 10, 20 and 30, respectively).
  • Micrograms are abbreviated mcg rather than µg (which, if handwritten, could easily be mistaken for mg (milligrams). Even so, pharmacists must be on the alert for inadvertent over- or under-prescribing through a momentary lapse of concentration.

Abbreviations

Many abbreviations are derived from Latin phrases. Hospital pharmacies have more abbreviations, some specific to the hospital. Different jurisdictions follow different conventions on what is abbreviated or not. Prescriptions that do not follow area conventions may be flagged as possible forgeries.

Some abbreviations that are ambiguous, or that in their written form might be confused with something else, are not recommended and should be avoided. These are flagged in the table in the main article. However, all abbreviations carry an increased risk for confusion and misinterpretation and should be used cautiously.

Non-Prescription Drug Prescriptions

Over-the-counter medications and non-controlled medical supplies such as dressings, which do not require a prescription, may also be prescribed. Depending upon a jurisdiction’s medical system, non-prescription drugs may be prescribed because drug benefit plans may reimburse the patient only if the over-the-counter medication is taken at the direction of a qualified medical practitioner. In the countries of the UK, National Health Service (NHS) prescriptions are either free or have a fixed price per item; a prescription may be issued so the patient does not have to purchase the item at commercial price.

Some medical software requires a prescription.

Legislation may define certain equipment as “prescription devices”. Such prescription devices can only be used under the supervision of authorised personnel and such authorisation is typically documented using a prescription. Examples of prescription devices include dental cement (for affixing braces to tooth surfaces), various prostheses, gut sutures, sickle cell tests, cervical cap and ultrasound monitor.

In some jurisdictions, hypodermic syringes are in a special class of their own, regulated as illicit drug use accessories separate from regular medical legislation. Such legislation often allows syringes to be dispensed only with a prescription.

Use of Technology

As a prescription is nothing more than information among a prescriber, pharmacist and patient, information technology can be applied to it. Existing information technology is adequate to print out prescriptions. Hospital information systems in some hospitals do away with prescriptions within the hospital. There are proposals to securely transmit the prescription from the prescriber to the pharmacist using smartcard or the internet. In the UK a project called the Electronic Transfer of Prescriptions (ETP) within the National Programme for IT (NPfIT) is currently piloting such a scheme between prescribers and pharmacies.

Within computerised pharmacies, the information on paper prescriptions is recorded into a database. Afterwards, the paper prescription is archived for storage and legal reasons.

A pharmacy chain is often linked together through corporate headquarters with computer networking. A person who has a prescription filled at one branch can get a refill of that prescription at any other store in the chain, as well as have their information available for new prescriptions at any branch.

Some online pharmacies also offer services to customers over the internet, allowing users to specify the store that they will pick up the medicine from.

Many pharmacies now offer services to ship prescription refills right to the patient’s home. They also offer mail service where you can mail in a new, original prescription and a signed document, and they will ship the filled prescription back to you.

Pharmacy information systems are a potential source of valuable information for pharmaceutical companies as it contains information about the prescriber’s prescribing habits. Prescription data mining of such data is a developing, specialised field.

Many prescribers lack the digitised information systems that reduce prescribing errors. To reduce these errors, some investigators have developed modified prescription forms that prompt the prescriber to provide all the desired elements of a good prescription. The modified forms also contain predefined choices such as common quantities, units and frequencies that the prescriber may circle rather than write out. Such forms are thought to reduce errors, especially omission and handwriting errors and are actively under evaluation.

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