Interpretation
  • If genotype CYP3A5*1/*1 or *1/*3 or *1/*other alleles are detected, this would be reported as normal to intermediate metabolizer
  • If genotype CYP3A5*3/*3 is detected, or if CYP3A5*1 allele is NOT detected, this would be reported as a poor metabolizer

The following is a list of major therapeutic classes with drugs that are substantially metabolized by CYP3A.

Statins: atorvastatin, simvastatin, lovastatin.

Calcium channel blockers: nifedipine, verapamil, nicardipine, felodipine, nisoldipine.

Antiplatelets: clopidogrel, prasugrel, ticagrelor, cilostazol.

Antiarrhythmics: amiodarone, quinidine, disopyramide, lidocaine.

Example of angina treatments: ranolazine.

Angiotensin II Inhibitors: losartan.

Anticoagulants: rivaroxaban, apixaban.

The following is a list of major inhibitors that compete with other drugs for a particular enzyme thus affecting the optimal level of metabolism of the substrate drug which in many cases affect the individual's response to that particular medication, e.g. making it ineffective.

Strong inhibitor is one that causes a > 5-fold increase in the plasma AUC values or more than 80% decrease in clearance. This include: indinavir, nelfinavir, ritonavir, clarithromycin, itraconazole, ketoconazole,nefazodone, saquinavir, telithromycin

Moderate inhibitor is one that causes a > 2-fold increase in the plasma AUC values or 50-80% decrease in clearance. This include: aprepitant, erythromycin, fluconazole, grapefruit juice, verapamil, diltiazem

A Weak inhibitor is one that causes a > 1.25-fold but < 2-fold increase in the plasma AUC values or 20-50% decrease in clearance such as cimetidine, amiodarone, chloramphenicol, boceprevir, ciprofloxacin, delaviridine, diethyl, dithiocarbamate, fluvoxamine, gestodene, imatinib, mibefradil, mifepristone, norfloxacin, norfluoxetine, starfruit, telaprevir, voriconazole