Enzyme

Medication Examples

Effect/Recommendation

CYP3A4 Substrates

Immunosuppressants, chemotherapeutics, antidepressants, antipsychotics, opioids, benzodiazepines, z-hypnotics, statins, calcium channel blockers, etc.

Increased risk of side effects related to substrate.

Avoid co-administration, reduce substrate dose, monitor for adverse effects, and toxicity.

Avoid prescribing cascade with new treatments for side effects.

CYP3A4 Inhibitors

Strong: Protease inhibitors, ketoconazole, loperamide, nefazodone.

Moderate: Amiodarone, verapamil, cimetidine, aprepitant, imatinib.

Increased CBD bioavailability, possible increase in adverse effects. Reduce CBD dose.

CYP3A4 Inducers

Strong: Enzalutamide, phenytoin.

Moderate: Carbamazepine, topiramate, phenobarbital, rifampicin, efavirenz, pioglitazone.

Decreased CBD dose availability, possible decrease in CBD effectiveness. Increase CBD dose.

CYP2C19 Substrates

Antidepressants, antiepileptics, proton pump inhibitors, clopidogrel, propranolol, carisoprodol, cyclophosphamide, warfarin.

Increased risk of side effects related to substrate.

Avoid co-administration, reduce substrate dose, monitor for adverse effects and toxicity.

Avoid prescribing cascade with new treatment for side effects.

CYP2C19 Inhibitors

Strong: Fluvoxamine, fluoxetine.

Other: Proton pump inhibitors, cimetidine, ketoconazole, clopidogrel, fluconazole, efavirenz.

Increased CBD bioavailability, possible increase in risk for adverse effects. Reduce CBD dose.

CYP2C19 Inducers

Rifampin, carbamazepine, phenobarbital, phenytoin, St. John’s Wort.

Decreased CBD bioavailability, possible decrease in CBD effectiveness. Increase CBD dose.

CYP2C8/9 Substrates

Rosiglitazone, buprenorphine, montelukast, celecoxib, sulfonylureas, losartan, naproxen, phenobarbital, phenytoin, rosuvastatin, valsartan, warfarin.

Increased risk of side effects related to substrate.

Avoid co-administration, reduce substrate dose, monitor for adverse effects and toxicity.

Avoid prescribing cascade with new treatment for side effects.