Genetic polymorphism of cytochrome P450 and methods for its determination.

The majority of human P450 dependent drug metabolism is carried out by polymorphic enzymes which can alter plasma concentration of the pharmacological active substance followed by an enhanced or suppressed pharmacological effect. The response of individual patients to drugs can be affected by variations in DNA sequence mainly by single nucleotide polymorphisms (SNPs). Knowledge of functionally important SNPs prior to the drug administrations may assist in the development of individualized pharmacotherapy avoiding unexpected drug responses, such as harmful adverse drug reactions or treatment failures. This review discusses both the basic characteristics of the major polymorphic cytochrome P450 enzymes and examines the pharmacogenetic methods employed to estimate metabolic status. We will focus mainly on the basic principles of genotyping assays involving molecular biology tools.