Table II.

Summary of Drug Dosing Recommendations Based on the Phenotype for 4 Genes and 12 Drugs Implemented as of August, 2013.

Drug	Gene	Phenotype	Dosing Recommendation
Codeine	CYP2D6	Ultra-rapid metabolizer	Change drug
		Extensive metabolizer	No change
		Intermediate metabolizer	No change
		Poor metabolizer	Change drug
Tramadol	CYP2D6	Ultra-rapid metabolizer	Change drug
		Extensive metabolizer	No change
		Intermediate metabolizer	No change
		Poor metabolizer	Change drug
Oxycodone	CYP2D6	Ultra-rapid metabolizer	Change drug
		Extensive metabolizer	No change
		Intermediate metabolizer	No change
		Poor metabolizer	Change drug
Amitriptyline	CYP2D6	Ultra-rapid metabolizer	Change drug
		Extensive metabolizer	No change
		Intermediate metabolizer	Reduce dose
		Poor metabolizer	Reduce dose/Change drug
Ondansetron	CYP2D6	Ultra-rapid metabolizer	Change drug
		Extensive metabolizer	No change
		Intermediate metabolizer	No change
		Poor metabolizer	No change
Fluoxetine	CYP2D6	Ultra-rapid metabolizer	Change drug
		Extensive metabolizer	No change
		Intermediate metabolizer	No change
		Poor metabolizer	Reduce dose
Paroxetine	CYP2D6	Ultra-rapid metabolizer	Change drug
		Extensive metabolizer	No change
		Intermediate metabolizer	No change
		Poor metabolizer	Reduce dose
Simvastatin	SLCO1B1	High function	No change
		Intermediate function	Reduce dose/change drug
		Low function	Change drug
Clopidogrel	CYP2C19	Ultra-rapid metabolizer	No change
		Extensive metabolizer	No change
		Intermediate metabolizer	Change drug
		Poor metabolizer	Change drug
Mercaptopurine Thioguanine Azathioprine	TPMT	High (normal) function	No change
		Intermediate function	Reduce dose
		Low or absent function	Reduce dose/change drug

For more detailed recommendations consult the corresponding CPIC guideline (http://www.pharmgkb.org/page/cpic) or other information on PharmGKB (http://www.pharmgkb.org).