Abstract
Pharmacogenetics is the study of genetic determinants of different responses to drug therapy and deals with differences in metabolic pathways and therapeutic effects as well as adverse reactions. A common genetic defect found in veterinary medicine is the MDR1 mutation occurring in Collies and related breeds that leads to an altered P-glycoprotein. Genetic mutations of enzymes (cytochrome P450, thiopurine s-methyltransferase, n-acetyltransferase, UDP-glucuronyltransferase, plasma esterase or sulfotransferase), which are responsible for the metabolism of drugs, are found as well. A decreased functional level of these enzymes can lead to an increased plasma concentration of the drug with a consequent relative overdose.
Jud Schefer, R S