Table 3.

Phenotypic effects of SNPs on drug metabolism

Drug given	Prodrug		Active drug
Metabolizer level	Poor	Rapid	Poor	Rapid
Drug exposure	Decreased conversion	Increased conversion	Decreased inactivation	Increased inactivation
Drug activity	Decreased efficacy	Increased efficacy	Increased efficacy	Decreased efficacy
Adverse effects	Increased if prodrug is toxic	Increased if active compound is toxic	Increased if drug is toxic	Decreased if drug is toxic Increased if drug is toxic