The pharmacology dictionary, in two languages.

A numeric value, assigned to each allele and summed across a diplotype, used mainly for CYP2D6 to translate genotype into a predicted metabolizer phenotype.

A peer-reviewed, evidence-based prescribing recommendation issued by the Clinical Pharmacogenetics Implementation Consortium for a specific gene–drug pair.

A cytochrome P450 enzyme that activates the prodrug clopidogrel to its antiplatelet metabolite and also metabolises proton pump inhibitors and several other drugs.

A highly polymorphic cytochrome P450 enzyme that metabolises a large number of drugs, including several opioids and antidepressants, and activates key prodrugs.

The gene encoding dihydropyrimidine dehydrogenase, the rate-limiting enzyme for inactivating fluoropyrimidine chemotherapy drugs, whose deficiency risks severe toxicity.

An X-linked inherited deficiency of glucose-6-phosphate dehydrogenase that leaves red blood cells vulnerable to oxidative stress, risking acute haemolysis with certain drugs.

A DNA sequence variation, such as a single-nucleotide change or a copy-number variant, present in more than about 1% of a population.

A human leukocyte antigen allele strongly associated with carbamazepine-induced Stevens–Johnson syndrome and toxic epidermal necrolysis, most prevalent in Southeast and South Asian ancestry.

A human leukocyte antigen allele strongly associated with a severe, immune-mediated hypersensitivity reaction to the antiretroviral drug abacavir.

A CPIC phenotype describing a person with reduced drug-metabolising enzyme activity, typically from one non-functional or decreased-function allele plus one normal-function allele.

The CPIC phenotype describing a person with two fully functional alleles of a drug-metabolising enzyme gene, giving the expected, population-typical level of enzyme activity.

The study of how inherited genetic variation affects an individual's response to drugs, used clinically to guide drug and dose selection.

A CPIC phenotype for a person carrying two non-functional (no-function) alleles of a drug-metabolising enzyme gene, resulting in little or no enzyme activity.

A phenotype defined by reduced N-acetyltransferase 2 (NAT2) activity, causing slower inactivation of drugs cleared by acetylation and greater exposure at standard doses.

A standardised naming system for a specific haplotype of a pharmacogenetically important gene, denoted by an asterisk followed by a number, such as CYP2D6*4.

Two enzymes whose genetic deficiency reduces inactivation of thiopurine drugs, causing excess active metabolite accumulation and a markedly increased risk of severe myelosuppression.

A CPIC phenotype for a person with increased drug-metabolising enzyme activity, often from a gene duplication or an increased-function allele, above the normal metabolizer range.

The gene encoding vitamin K epoxide reductase complex subunit 1, the pharmacological target of warfarin, whose promoter variants alter warfarin dose requirement.