Table 3.

Specific PGx CDS Recommendations for Each of the PGx Variants Tested

Drug–gene interaction	Phenotype	Recommendation
Simvastatin–SLCO1B1	TT (normal activity)	Standard dosing
TC (intermediate)	Intermediate myopathy risk; reduce simvastatin dose or consider alternative therapy
CC (poor)	High myopathy risk; avoid simvastatin and use alternative therapy
Clopidogrel–CYP2C19	Ultrarapid metabolizer	Standard dosing
Extensive to ultrarapid metabolizer	Standard dosing
Extensive (normal) metabolizer	Standard dosing
Intermediate to extensive metabolizer	Standard dosing
Intermediate	Clopidogrel efficacy reduced; consider alternative therapy
Poor to intermediate metabolizer	Clopidogrel efficacy reduced; consider alternative therapy
Poor metabolizer	Clopidogrel efficacy significantly reduced; consider alternative therapy
Warfarin–CYP2C9/VKORC1		Initial warfarin dose is calculated and displayed
Codeine–CYP2D6 Tramadol–CYP2D6	Ultrarapid metabolizer	Avoid codeine/tramadol because of potential for toxicity
Extensive to ultrarapid metabolizer	Increased toxicity such as respiratory depression may occur; caution is advised with codeine/tramadol
Extensive metabolizer (normal)	Standard dosing
Intermediate to ultrarapid metabolizer	Reduced efficacy may occur if an intermediate metabolizer or risk of toxicity may occur if an ultrarapid metabolizer; caution is advised, and alternative therapy other than codeine/tramadol might be considered
Intermediate to extensive metabolizer	Standard dosing
Intermediate metabolizer	Standard dosing
Poor to intermediate metabolizer	Efficacy may be reduced for codeine/tramadol; other treatments should be considered
Poor metabolizer	Avoid codeine/tramadol because of lack of efficacy

CDS, clinical decision support; PGx, pharmacogenomics.