Resources

absorption

The intent of drug administration is for the active component of the drug to reach the site of action and initiate a series of events that will culminate in a drug effect. The sum of all the processes that are entailed in the movement of the drug from the site of administration to the inside of the body is considered to be absorption. For most practical purposes, administration is considered to be complete when all of the drug has entered the circulatory system and is thus being distributed to the rest of the body. Using this definition, intravenous administration does not involve absorption since the drug is placed directly into the circulatory system.

absorption rate constant (ka)

k_adefines the absorption rate constant, the rate of absorption of a drug absorbed from its site of application according to first-order kinetics, for a drug administered by a route other than intravenously.

acid

An acid is a compound that acts as a proton donor. Thus, a compound that gives up a hydrogen ion (H⁺) is an acid. An acidic solution is one in which the pH (see pH) is below 7.00 and thus has a relative abundance of H⁺ ions. A compound may be called a weak or strong acid. This indicates that the pH at which 50% of the compound is ionised when in solution is close to 7 (weak) or close to 1 (strong)

action potential

The action potential is a brief (approx 1–10 msec) change in the electrical charge across the membrane of a nerve or muscle cell. The change in membrane potential is a result of changes in the distribution of ions (particularly Na⁺ and K⁺). Prior to an action potential the charge across the membrane is held relatively constant (e.g. –70mV); this is referred to as the resting potential. In neurons, this is primarily achieved by the slow leak of K⁺ out of the cell, which yields a net negative charge with the inside of the cell being negative relative to the outside. This resting potential is maintained as long as the flow of ions is not disturbed. However, if the membrane is depolarised (charge moved toward 0), this will cause voltage-dependent sodium channels to open, allowing sodium to flow into the cell and causing the inside of the cell to become positively charged. Subsequently the Na⁺ channels close, and there is a rapid movement of K⁺ out of the cell as K⁺ channels increase their conductance. The extracellular flow of K⁺ results in recovery of the negative potential across the cell membrane (repolarisation). When viewed in graphical form (mVolts vs. time) the rapid change in charge appears as a spike. The whole series of events from resting potential to depolarisation to repolarisation is referred to collectively as the action potential.

active transport

Transport refers to the movement of molecules or ions across a biological membrane (e.g. into a cell). In active transport, energy is expended to transport the molecules from one side of the membrane to another. Since energy is required, active transport implies that the transport is from an area of lower concentration to an area of higher concentration (i.e. against the concentration gradient).

addiction

A maladaptive pattern of substance use leading to clinically significant impairment or distress. A dependent individual will spend a great deal of time in drug-seeking, drug-taking and recovery activities, and will persist in taking the drug despite adverse social, occupational or recreational outcomes, and in full knowledge of the psychological and physical problems resulting from their drug-taking.

adherence

The degree to which a person takes a medication as recommended by a health care provider.

adsorption

The process by which a drug adheres to a surface. Drugs can adsorb to particles or proteins.

adverse drug event

An unwanted and sometimes unintended effect that occurs while a person is taking a drug.

adverse drug reaction (ADR)

The Medicines and Healthcare Regulatory Agency (MHRA) describes an adverse drug reaction (ADR) as a response to a medicinal product which is noxious and unintended. Response in this context means that a causal relationship between a medicinal product and an adverse event is at least a reasonable possibility. Adverse reactions may arise from use of the product within or outside the terms of the marketing authorisation or from occupational exposure. Conditions of use outside the marketing authorisation include off-label use, overdose, misuse, abuse and medication errors. The reaction may be a known side effect of the drug or it may be new and previously unrecognised.

affinity

Affinity is a measure of the equilibrium constant of the reversible reaction of a drug with a receptor to form a drug-receptor complex; the reciprocal of the dissociation constant of a drug-receptor complex.

agonist

A compound that binds to and activates a receptor. Can be full, partial or inverse.

Full agonists have high efficacy, producing a full response while occupying a relatively low proportion of receptors.
Partial agonists have lower efficacy than a full agonist. They produce sub-maximal activation even when occupying the total receptor population, therefore cannot produce the maximal response, irrespective of the concentration applied.
Inverse agonists produce an effect opposite to that of an agonist, yet binds to the same receptor binding-site as an agonist.

Recommendations regarding the use of terms and symbols used in receptor pharmacology are provided in International Union of Pharmacology Committee on Receptor Nomenclature and Drug Classification. XXXVIII. Update on terms and symbols in quantitative pharmacology.

alkylating agent

Agents that damage DNA and prevent cells from proliferating; used to treat many different cancers. classical antineoplastic alkylating agents are melphalan and chlorambucil.

allele

A variant form of a gene.

allosteric modulator

A compound that binds to a receptor at a site distinct from the active site (agonist binding site). Induces a conformational change in the receptor, which alters the affinity of the receptor for the endogenous ligand. Positive allosteric modulators (PAMs) increase the affinity, whilst negative allosteric modulators (NAMs) decrease the affinity.

analgesic

A drug that dulls the sense of pain. It differs from an anesthetic agent in that it relieves pain without loss of consciousness.

anaphylaxis

A severe rapid onset inflammatory reaction that is a medical emergency and requires immediate intervention. Often caused by allergies to insect bites and stings, food allergies and allergies to medications. Epinephrine (adrenaline) is the primary treatment for anaphylaxis.

anesthetic

Alternative spelling, anaesthetic. A drug that causes loss of sensation. General anesthetics cause loss of sensation and loss of consciousness. Local anesthetics cause loss of sensation by blocking nerve conduction only in the particular area where they are applied.

anorectic

Anorectic drugs are appetite suppressants. Also known as anorexics, anorexigenic or anorexiant agents. Examples include amphetamine (and derivatives), methylphenidate (Ritalin), and the anti-convulsants topiramate and zonisamide, which all have weight-loss as a side-effect.

antagonist

A compound that attenuates the effect of an agonist. Can be competitive or non-competitive, each of which can be reversible or irreversible.

A competitive antagonist binds to the same site as the agonist but does not activate it, thus blocks the agonist’s action.
A non-competitive antagonist binds to an allosteric (non-agonist) site on the receptor to prevent activation of the receptor.
A reversible antagonist binds non-covalently to the receptor, therefore can be “washed out”.
An irreversible antagonist binds covalently to the receptor and cannot be displaced by either competing ligands or washing.

area under the curve (AUC)

AUC is the area under the plot of plasma concentration of drug (not logarithm of the concentration) against time after drug administration. The AUC is of particular use in estimating bioavailability of drugs, and in estimating total clearance of drugs. The ratio of the AUC after oral administration of a drug formulation to that after the intravenous injection of the same dose to the same subject is used during drug development to assess a drug’s oral bioavailability.

autacoids

Autacoids are biological factors which act like paracrine hormones: typically having a brief duration of action near the site of synthesis. Examples are histamine and serotonin.

autocrine

Pertaining to the release of signalling molecules which act directly via receptors on the same cell. For example, vascular endothelial growth factor (VEGF) produced by some types of cancer cells, acts in a autocrine manner to promote their own survival and migration.

bias

Bias is the deviation of results from the truth, due to systematic error in the method used. There are many different types of bias.

bioassay (or biological assay)

Used to determine the potency of a physical, chemical or biological agent, by means of a biological indicator i.e. measuring the response of living organisms or tissues to a test treatment.

bioavailability

Bioavailability (or simply availability) is an indicator of the percent of a drug dose entering the systemic circulation after administration of a given dosage form. The amount of drug absorbed is taken as a measure of the ability of the formulation to deliver drug to the sites of drug action. More explicitly, the ratio of the amount of drug “absorbed” from a test formulation to the amount “absorbed” after administration of a standard formulation. Frequently, the “standard formulation” used in assessing bioavailability is the aqueous solution of the drug, given intravenously.

bioequivalence

A term that indicates the biological (or pharmacological) equivalence of two proprietary preparations of a drug in terms of their pharmacokinetics when administered in the same way, at the same molar dose.

biomarker

A measurable indicator of a biological process.

biopharmaceutics

The science and study of the ways in which the pharmaceutical formulation of administered agents can influence their pharmacodynamic and pharmacokinetic behavior. Differences in pharmaceutical properties can cause substantial differences in the biologic properties – and therapeutic usefulness – of preparations which are identical with respect to their content of active ingredient.

biotransformation

Factors that act to convert a drug to another form. Typically, in the process of drug elimination drugs are biotransformed to inactive, more polar, water-soluble products that can be more easily excreted in the urine. However, the products of biotransformation can also be active compounds in themselves, or may be toxic. The major organ of biotransformation is the liver.

biotranslocation

The movement of drugs into, through, and out of biological organisms or their organs/tissues. The study of biotranslocation determines how chemicals cross cellular membranes and other biological barriers.

blind experiment

A form of experiment in which the participants are, to some degree, kept ignorant of the nature and doses of materials administered during the experiment, to prevent a prejudiced interpretation of the drug effects observed, and to prevent a presumed knowledge of effects to be expected from influencing the kinds of effects manifested by a subject. In a ‘single-blind’ experiment, one participant – usually the subject – is left uninformed. In a ‘double-blind‘ experiment two participants – usually the subject and observer – are uninformed, and in ‘triple-blind‘ experiment the subject, the observer, and the person responsible for the actual administration of the drug are left unaware of the nature of the material administered. In clinical experimentation the use of blind experimentation is frequently associated with the use of dummy or placebo medication as part of the experimental design, and the use of a ‘cross-over’ experimental design.

Bmax

The maximum amount of drug or radioligand, usually expressed as picomoles (pM) per mg protein, which can bind specifically to the receptors in a membrane preparation. B_max be used to measure the density of receptor sites in a particular test sample.

bradypnoea

abnormally slow breathing rate; respiratory depression

bruxism

Medical term for grinding the teeth and clenching the jaw.

chemotherapy

Drug treatment of parasitic or neoplastic disease in which the drug has a selective effect on the invading cells or organisms.

Cheng-Prusoff equation

The Cheng-Prusoff equation is used to determine the K_i value from an IC₅₀ value measured in a competition radioligand binding assay:

Where [L] is the concentration of free radioligand, and K_d is the dissociation constant of the radioligand for the receptor.

chromatin

A complex of DNA and proteins within the nucleus of mammalian cells.

clearance rate

Often simply called drug clearance, this is a measure of the efficiency of solute removal by the body or specific organs (e.g., the liver or kidney). When an organ is not specified, it refers to the total body clearance rate.

clearance/drug clearance

A fundamental pharmacokinetic term that refers to the ability of the body to eliminate a drug. The term is borrowed from renal physiology and is based on the concepts developed for creatinine clearance. It is defined as: Clearance = (rate of elimination)/ (concentration of drug in biofluid). The biofluid can be blood, plasma or other relevant fluid. Total body clearance is the sum of clearance by renal, liver and other drug elimination mechanisms.

Cmax, Cmin

C_max is the maximum or ‘peak’ concentration of a drug observed after its administration. The C_min, or trough concentration is observed after drug administration and just prior to the administration of a subsequent dose.

cohort studies

Cohort studies provide the best information about causation of disease and the most direct measurement of the risk of developing a disease or condition. They begin with a group of people who are free from disease but have been exposed to a potential cause. The cohort is then followed up to monitor the subsequent development of new cases.

compartment(s)

The space or spaces in the body, which a drug appears to occupy after it has been absorbed. Compartments in which equilibrium is achieved relatively late are referred to as “deep” compartments; compartments in which equilibrium is achieved early – and from which drug is redistributed to other sites – are referred to as “shallow” or “superficial” compartments.

concentration

In clinical settings, this is defined as an amount of drug per defined volume of body fluid. It is often expressed as a mass of drug per mL of plasma or serum.

cross-over experiment

A form of experiment in which each subject receives the test preparation at least once, and every test preparation is administered to every subject. At successive experimental sessions each preparation is “crossed-over” from one subject to another. The purpose of the cross-over experiment is to permit the effects of every preparation to be studied in every subject, to allow for the effects of individual differences in response.

dependence

a.k.a. drug dependence, which is a somatic state which develops after chronic administration of certain drugs. The dependent state is characterized by the necessity to continue administration of the drug in order to avoid the appearance of uncomfortable or dangerous (withdrawal) symptoms.

desensitization (desensitisation)

A reduction in response to an agonist while it is continuously present at the receptor, or progressive decrease in response upon repeated exposure to an agonist.

distribution

A term used to refer to the disposition of drug throughout the body following drug absorption.

dosage

The amount (i.e., quantity) of drug administered per unit of time. The dosage takes into consideration the frequency of dosing.

dose

The amount (i.e., quantity) of drug administered.

drug

A drug is a medicine or other substance which has a physiological effect when introduced into the body; a substance used in the diagnosis, treatment, or prevention of a disease or as a component of a medication.

drug transporter

A protein that assists a drug in entering or exiting a cell or organelle. Drug transporters are involved in passive diffusion, facilitated diffusion, and/or active drug transport against a concentration gradient.

Dyscrasia

An abnormal or disordered state of the body or of a bodily part. For example, blood dyscrasia is a pathological condition in which any of the components of the blood (usually cellular components) are abnormal in structure, function, or quality, as in leukemia or hemophilia.

dystonia

Dystonia is a state of abnormal muscle tone resulting in muscular spasm and abnormal posture. Dystonia typically results from neurological disease or can be a side effect of certain drugs.

EC50

EC₅₀ defines the molar concentration of an agonist that produces 50% of the maximum possible response for that agonist.

ED50

ED₅₀ defines the dose of compound that produces 50% of its maximum response or effect in vitro or in vivo.

effectiveness

The ability of a drug to elicit a defined response (i.e., size or strength of a response) under normal conditions. It reflects the efficacy of a drug in real-world situations as opposed to the controlled conditions of scientific research studies.

efficacy

Efficacy describes the way that agonists vary in the response they produce when they occupy the same number of receptors.

High efficacy agonists produce their maximal response while occupying a relatively low proportion of the total receptor population.
Lower efficacy agonists do not activate receptors to the same degree and may not be able to produce the maximal response.

elimination

The process by which a drug is eliminated due to biotransformation to a different molecule called a drug metabolite or excretion (i.e., removal of the drug from the body).

elimination rate constant

A value denoted by K_e (or K_el) that reflects the rate of elimination of drug per unit time in a biological system and can be calculated by dividing ln 2 (~0.693) by the half-life (t_1/2) of the drug for drugs that are eliminated by first-order elimination kinetics.

Emax

E_maxis the value that reflects the maximal response a drug can produce in a particular tissue. It is determined by measuring responses to several increasing concentrations of drug in a biological system.

endocrine

Pertaining to glands which secrete hormones (or other products) directly in to the blood. Endocrine factors generally take effect as sites distant from their release site.

enteral administration

Enteral administration routes include the oral, sublingual and rectal routes. Enteral administration facilitates systemic exposure to the drug.

epigenetics

The study of heritable changes in phenotype that does not involve changes in the underlying DNA sequence.

euchromatin

A loosely packed form of chromatin that is typically actively being transcribed or is accessible for transcription.

ex vivo

Taking place outside a living organism.

excretion

The removal of a drug from the body, often in urine, feces, sweat, saliva, or breast milk.

exocrine

Pertaining to glands which secrete hormones (or other products) to an epithelial surface via ducts rather than directly in to the bloodstream (cf. endocrine). Exocrine glands include the salivary and sweat glands, and glands within the gastrointestinal tract.

first pass effect

First pass effect is the biotransformation and/or excretion of a drug by intestinal and hepatic mechanisms (including biliary) following absorption of the drug from the gastrointestinal tract, before the drug gains access to the systemic circulation.

first-order kinetics

Used to refer to when a constant proportion of drug in a biological system is eliminated per unit of time.

generic drugs

Generic drugs are formulations of identical composition with respect to the active ingredient, i.e., drugs that meet current official standards of identity, purity, and quality of active ingredient. Drug dosage forms considered as “generically equivalent” are more properly considered as “chemically equivalent” in that they contain a designated quantity of drug chemical in specified stable condition and meet pharmacopoeial requirements for chemical and physical properties.

genetic assimilation

A process in which an environmentally induced phenotype, or ‘acquired characteristic’, becomes genetically fixed even in the absence of the original stimulus that induced the phenotype.

genetic variant

An alteration from the wild-type DNA sequence.

genotype

The inherited genetic makeup of a cell.

graded dose-response curve

A plot of the dose (or concentration) of drug on the x-axis versus a measured response to that drug on the y-axis.

habituation

A condition characterized by a psychological craving for the effects produced by the administration of a drug, as a desire rather than a compulsion, and an absence of physical dependence.

haemolysis (hemolysis)

Haemolysis is the rupture (lysis) or destruction of erythrocytes. Haemolysis can be caused by bacterial toxins (e.g. Gram +ve Streptococcal, Enterococcal or Staphylococcal toxins), parasites (e.g. Plasmodium sp.), autoimmune or genetic disorders, and can lead to haemoglobinemia (hemoglobinemia).

half-life

Half-life (t_½) is an important pharmacokinetic measurement. The metabolic half-life of a drug in vivo is the time taken for its concentration in plasma to decline to half its original level. Half-life confers the duration of action of a drug and depends upon how quickly the drug is eliminated from the plasma. The clearance and distribution of a drug from the plasma are therefore important parameters for the determination of its half-life.

haplotype

A set of genetic variants that are inherited together.

hepatic drug clearance rate

Often referred to simply as hepatic clearance, this represents the rate at which the liver is able to remove drug during. It is influenced by the rate of blood flow to the liver and the efficiency of the liver to remove drug from the blood, which is reflected by the hepatic extraction ratio.

hepatic extraction ratio

The fraction of drug entering the liver in the blood that is irreversibly removed during a single pass through the liver.

heterochromatin

A tightly packed form of chromatin that is not actively being transcribed or is less accessible for transcription

histones

Eukaryotic proteins around which DNA is tightly wound. Histones function to condense and package DNA in the nucleus.

i.a.

i.a. refers to drug administration via the intra-arterial route.

i.c.

i.c. refers to drug administration via the intracerebral route.

i.c.v.

i.c.v. refers to drug administration via the intracerebroventricular route.

i.d.

i.d. refers to drug administration via the intradermal route.

i.g.

i.g. refers to drug administration via the intragastric route.

i.m.

i.m. refers to drug administration via the intramuscular route.

i.p.

i.p. refers to drug administration via the intraperitoneal route.

i.t.

i.t. refers to drug administration via the intrathecal route.

i.v.

i.v. refers to drug administration via the intravenous route.

IC50

IC₅₀ defines the molar concentration of an agonist or antagonist which produces 50% of its maximum possible inhibition in a functional assay. In a radioligand binding assay, IC₅₀ defines the molar concentration of competing ligand which reduces the specific binding of a radioligand by 50%.

ID50

ID₅₀ defines the dose of a drug that causes 50% of the maximum possible inhibition for that drug in vitro or in vivo.

immunopharmacology

Immunopharmacology is the branch of pharmacology concerned with the application of immunological techniques and theory to the study of the effects of drugs especially on the immune system.

imprint disorder

An abnormal state resulting from the process of genetic imprinting in which a gene is not transcribed due to an epigenetic modification such as methylation.

in vitro

In vitro refers to experiments taking place in a test-tube, culture dish or elsewhere outside a living organism.

in vivo

In vivo refers to experiments or assessments being made in a living organism.

insufflation

Insufflation in medical terms is a route of drug administration used for many respiratory drugs, such as emphysema, asthma and allergy medications. It is the act of inhaling a gas, powder or vapor in to the body. Nasal insufflation (= nasal administration) is becoming more widely used to administer certain types of drugs to children, and patients with a needle aversion e.g. nasal administration of influenza inoculation, although this method more correctly sprays the vaccine in to the nasal cavity, rather than the patient actively inhaling it.

There are no entries here.

KB

K_B defines the equilibrium dissociation constant for a competitive antagonist: i.e. the molar concentration that would occupy 50% of the receptors at equilibrium.

Kd

K_d defines the dissociation constant (a.k.a. equilibrium dissociation constant) for a radiolabeled ligand determined by saturation binding analysis. It is the molar concentration of radioligand which, at equilibrium, occupies 50% of the

receptors.

Ki

K_i defines the inhibition constant for a ligand, which denotes the affinity of the ligand for a receptor. Measured using a radioligand competition binding assay, it is the molar concentration of the competing ligand that would occupy 50% of the receptors if no radioligand was present. It is calculated from the IC₅₀ value using the Cheng-Prusoff equation.

LOAEL

Lowest Observed Adverse Effect Level. This is the dose or concentration at which you first see an effect following increasing drug exposure. Often used in toxicology, it reflects the lowest dose that can elicit a response. Often this is determined in an animal or cell culture model.

membrane

An enclosing or separating membrane that acts as a selectively permeable barrier within living things, establishing the outer boundaries (plasma membranes) of cells and their inner compartments (organelles). Biological membranes are made of three major components: lipids, proteins and sugars. The major structural component of biological membranes is the phospholipid bilayer.

MEMS

Refers to a medication event monitoring system that is used to assess drug adherence, by recording each time it is opened to obtain a drug product.

metabolic drug tolerance

This term is often used in substance use disorders to describe a situation where more drug is needed to achieve the same effect due to a pharmacokinetic change associated with chronic or repeated drug use. It is often due to an increase in drug elimination resulting from increased drug biotransformation.

metabolism

In pharmacology, this term refers to the process of biotransformation, usually by enzymes, where one chemical species is converted to another. A parent compound is metabolized to a metabolite. The metabolite is the by-product of the reaction and may be less, more, or equal in activity (therapeutic or adverse) to the parent compound.

metabolite

The product of a biotransformation reaction, often used to refer to the resulting chemical or chemicals produced from an administered drug or prodrug.

nociception

Nociception (nocioception or nociperception) is the sensing of noxious stimuli of chemical, mechanical or thermal origin. These stimuli activate nociceptors, which transmit the signal through the spinal cord to the somatosensory cortex of the brain, where it is decoded as pain. The sensation of pain triggers a biological or behavioural response aimed to remove or counteract the noxious stimulus.

non-coding RNA

Abbreviated to ncRNA: RNA molecules which are not transcribed and whose function is to regulate gene expression at the transcriptional and post-transcriptional level. Epigenetic related ncRNAs include miRNA (micro RNA), siRNA (small interfering RNA), piRNA (piwi RNA) and lncRNA (long non-coding RNA)

non-specific binding

Non-specific binding refers to the proportion of radioligand that is not displaced by other competitive ligands specific for the receptor in a radio-ligand binding assay. It can be caused by radioligand binding to other receptors or proteins, partitioning into lipids or binding to other things, including experimental plastic- or glassware.

nootropic

Nootropics are drugs, dietary supplements, or other substances that are used by healthy individuals to improve cognitive function. Nootropics are also known as smart drugs or cognitive enhancers. Widely used nootropics include stimulants such as caffeine, and the ADHD drug methylphenidate (a norepinephrine and dopamine reuptake inhibitor).

nosocomial

This term broadly covers any disease contracted by a patient while under medical care, but has come to be used synonymously with ‘hospital-acquired’ when referring to infections such as Clostridium difficile, Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa.

nucleosome

A defined DNA-histone complex, consisting of 146 base pairs of double-stranded DNA wrapped around eight histone proteins.

orexigenic

Orexigenic agents are appetite stimulants. These can be endogenous hormones (e.g. ghrelin, orexin or neuropeptide Y) or agents administered as drugs; tricyclic antidepressants (TCAs), natural or synthetic cannabinoids, some first-generation antihistamines, and many antipsychotics and steroid hormones all act as orexigenics.

p.o.

p.o. refers to drug administration via the oral route, i.e. by mouth.

pA2

pA₂ is ameasure of the potency of an antagonist. It is the negative logarithm of the molar concentration of an antagonist that would produce a 2-fold shift in the concentration response curve for an agonist.

paracrine

Pertaining to the release of hormones (or other signalling molecules) which diffuse over a relatively short distance to act on nearby cells to affect changes in their function, growth or behavior. Fibroblast growth factors, hedgehog proteins, Wnt proteins and TGF-β peptides are paracrine factors.

parent compound

The starting compound in a biotransformation reaction.

parenteral administration

Parenteral administration routes do not involve the gastrointestinal tract and include intravenous, subcutaneous, intracerebral, intrathecal and intramuscular injection or infusion. Parenteral administration facilitates systemic exposure to the drug. In emergency situations and intensive care medicine parenteral administration is the most rapid and reliable method of drug delivery.

pD2

pD₂is the negative logarithm of an EC₅₀ or IC₅₀ value.

pharmacodynamics

Refers to what an administered drug does to the body. It refers to the actions (beneficial or harmful) of the drug.

pharmacoeconomics

A branch of health economics that applies economic considerations to drug therapy.

pharmacogenetics

The study of the effect of individual genes on drug response or action.

pharmacogenomics

The study of the effect of the genome on drug response or action.

pharmacokinetics

Refers to what the body does to an administered drug. It encompasses drug absorption, distribution, metabolism, and excretion.

pharmacology

Broadly defined as the study of drugs. It encompasses both how the body handles a drug as well as what a drug does to the body.

phenotype

The observable physical traits or biochemical characteristics of an organism based on a combination of the organism’s genes and environmental factors.

pIC50

pIC₅₀ is the negative logarithm of the IC₅₀ value.

pKa

Defined as the negative log of the acid dissociation constant (Ka), it is a measure of the strength of an acid.

pKB

pK_B is the negative logarithm of the K_B value.

pKd

pK_d is the negative logarithm of the K_d value.

pKi

pK_iis the negative logarithm of the K_i value.

potency

Potency is a measure of the concentration of a drug at which it is effective.

primary prevention

Primary prevention aims to prevent disease before it occurs. Examples include immunization against infectious diseases, and the use of statins to prevent cardiovascular disease.

prodrug

A drug that requires activation, generally by biotransformation enzymes, to have its therapeutic effect. The parent compound does not have significant if any therapeutic activity.

There are no entries here.

s.c.

s.c. refers to drug administration via the subcutaneous route.

secondary prevention

Secondary prevention aims to reduce the impact of an existing disease, by detecting and treating the it as soon as possible with the aim of halting or at least slowing its progress. Examples of secondary preventions include the use of regular screening programs to detect disease at its earliest stage (e.g. breast and bowel cancer screening) and taking low-dose aspirin alongside dietary changes and exercise to prevent further heart attacks or strokes.

silent antagonist

A silent (or neutral) antagonist is a compound that attenuates the effects of agonists or inverse agonists, producing a functional reduction in signal transduction. Affects only ligand-dependent receptor activation and displays no intrinsic activity itself.

spare receptors

A situation where there is an excess or reserve of receptors such that an agonist can elicit a full response without activating 100% of the receptors present. The effect may result from a downstream pathway following receptor binding.

specific binding

Specific binding refers to the proportion of radioligand that can be displaced by competitive ligands specific for the receptor, i.e. that is directly attributable to binding to the test target.

statin

Statin drugs (e.g. simvastatin, atorvastatin), more correctly known as HMG CoA reductase inhibitors, block the rate limiting step in cholesterol synthesis in the liver. This, in turn, stimulates the expression of increased numbers of LDL receptors on hepatocytes to increase the uptake of cholesterol-rich LDL lipoprotein particles from the circulation. Statins are indicated for the primary and secondary prevention of cardiovascular disease.

substance use disorder

A condition where a person administers a drug even though such drug use causes significant impairment or distress. This is used to describe problematic drug use such as the consumption of illicit or misused substances.

sumoylation

Describes the post-translational conjugation of SUMOs (small ubiquitin-like modifiers) to proteins. SUMOylation is involved in various cellular processes, including nuclear-cytosolic transport, transcriptional regulation, apoptosis, protein stability, response to stress, and progression through the cell cycle.

systemic

Systemic refers to agents that act in the peripheral tissues of the body, not in the central nervous system.

tachyphylaxis

A reduced response from a drug when it is administered repeatedly or chronically. This term is usually used when the reduction in response is rapid.

tachypnoea

abnormally rapid breathing (>20 breaths per minute in adults).

tertiary prevention

Tertiary prevention (or intervention) aims to lessen the impact of an ongoing illness (or injury) that has long-term effects, i.e. helping patients to manage chronic, often-complex health problems and injuries such as chronic diseases and physical disabilities. The goal of tertiary prevention is to improve the patient’s ability to function, their quality of life and their life expectancy, as much as is possible. Examples of tertiary interventions include cardiac or stroke rehabilitation programs, patient participation in support groups and occupational health service support (including vocational rehabilitation).

therapeutic drug monitoring

The process of determining drug concentrations in individual patients. This is often performed for drugs with a low therapeutic index where drug concentrations correlate with a beneficial or toxic effect(s).

therapeutic index

This is a measure of the relative safety of a drug calculated by dividing the lethal dose of a drug in 50% of a population (often derived from animal or cellular studies) by the effective dose in 50% of a population.

tolerance

A condition characterized by a reduced effect of a drug upon repeated administration, such that it becomes necessary to increase the dose of the drug to achieve the same effect. Tolerance typically develops over days to weeks.

topical administration

Topically administered drugs are applied to the site of action with the intention of localising drug action. Examples are optical solutions, local anesthetics, inhaled asthma drugs and anti-inflammatory creams applied to pruritic skin. Topically applied drugs can also achieve systemic exposure. For example, volatile anesthetics are administerd by inhalation but travel to the brain to take effect.

toxicology

The study of the adverse effects of chemicals and physical agents on biological systems.

transdermal administration

Transdermal administration is a method of drug application used for some drugs which are poorly absorbed from the digestive tract, and where patient convenience is sought (e.g. to avoid parenteral routes).

t½

Abbreviation used for biological half-life.

ubiquitination

Describes the addition of ubiquitin to a substrate protein. One important function of ubiquitination is targeting proteins to the proteasome for degradation.

volume of distribution

Volume of distribution (V_d or V_D) defines the distribution of a drug between the blood plasma and other bodily tissues after oral or parenteral administration. V_D can be considered as the size of the compartment in to which the drug distributes following absorption. It is the theoretical volume that would be necessary to contain the total amount of an administered drug at the same concentration that it is observed in the blood plasma. The higher the V_D, the greater the degree of drug distribution in to the tissues.

wild-type (genetics)

The most common gene allele in a population.

withdrawal

A term associated with the presence of adverse effects that occur when a person stops taking a drug or reduces its dosage. Withdrawal contributes to drug-seeking behaviour in problematic drug use. When a person requires a drug to avoid withdrawal symptoms, the person is considered to have drug dependence.

xenobiotic

A xenobiotic is any foreign chemical substance found in an organism that is not normally naturally produced by or expected to be present in that organism. Drugs are xenobiotics, as are environmental pollutants, food additives, carcinogens and pesticides.

There are no entries here.