Glossary

A

Area under the curve: (AUC) is a term used in pharmacokinetics (as displayed on a graph) to demonstrate the differences between different people in how quickly they process a drug and remove it from their body (Clearance).
Measuring the blood for the amount of the parent drug at different time intervals will show how quickly the drug becomes available to them i.e. the physical breakdown of the medication into its useful form, the processing by the enzymes and when it has left the body and no longer has an effect . The larger the value for AUC in general the more medication there is in the bloodstream.

C

Clearance: is the time taken from taking the drug (usually by swallowing) to the time it is finally eliminated from the body (usually in the urine).
This involves the stages of absorbing it into the blood (via the stomach and gut), then processing it by getting it into its useful form or active state and/or breaking it down from an active state to an inactive state (usually carried out by enzymes in the liver) and then eliminating it in the urine (via the kidneys).

Clearance time: is the same as clearance. It can be affected at any of these stages by several factors which include the general differences between people such as their body make-up e.g. weight, height, age, sex, fat distribution but also other substances that may inhibit or enhance the process such as certain foods, alcohol or smoking, and also some medical conditions that affect the liver or kidneys. Genetics will play a large part in the general make-up of the body but also in the individual enzymes involved in the processing of the drugs.

G

Generic name: This is the agreed official name for the drug.

M

Metaboliser: This is a term which categorises people on how fast they process (metabolise) the medication. The description of the process is called metabolism.

Metabolism: describes how certain drug is being processed in the body.

Metabolite: describes the various breakdown products from the parent drug of which there could be many and it may be active or inactive ie have therapeutic effect or not. An active metabolite is a chemical product that has some of the same action as the drug itself. ie the drug is not inactivated. The description of the process is called metabolism

P

Pharmacodynamics: Pharmacodynamics is the study of what a drug does to the body.(e.g., by mimicking or inhibiting normal biological or physiological reactions by a reaction that depresses activity, stimulates activity, destroys cells or replaces a substance).

Pharmacokinetics: This is the term for what the body does to the drug, ie how it processes the drug.

S

Seratonin syndrome: This is a severe side effect when two drugs that increase serotonin are used together or occasionally when one is used by itself in high doses. The nervous system is stimulated to cause tremor, incoordination and mental changes such as confusion and agitation. There can be sweating, shivering and a fever, as well as diarrhoea.

SNPs: The ‘letters' of DNA are molecules called nucleotides: adenine, cytosine, guanine, and thymine (A,C,G,T) strung together in long chains called sequences. The occasional single-letter differences that distinguish DNA among people are called single-nucleotide polymorphisms (SNPs)
Therapeutic drug monitoring (TDM). This refers to blood testing the level (concentration) of the drug
Therapeutic Index: this is a figure that measures the safety of the drug by calculating the ratio of the toxic dose to the dose that 50% of the tested subjects show an effective therapeutic response. The larger the therapeutic index the safer the drug (wide therapeutic index). If this ratio is low then there is a narrow therapeutic index and individual variations can easily range between ineffective dose and a dose that is toxic. Drugs , such as warfarin, with a narrow therapeutic index are ideal for the use of pharmacogenomic tests 

T

Therapeutic drug monitoring (TDM): This refers to blood testing the level (concentration) of the drug

Therapeutic Index: this is a figure that measures the safety of the drug by calculating the ratio of the toxic dose to the dose that 50% of the tested subjects show an effective therapeutic response. The larger the therapeutic index the safer the drug (wide therapeutic index). If this ratio is low then there is a narrow therapeutic index and individual variations can easily range between ineffective dose and a dose that is toxic. Drugs , such as warfarin, with a narrow therapeutic index are ideal for the use of pharmacogenomic tests

Trade name: This is also called proprietary name. It is the name the manufacturer uses.