OBJECT DRUGS
Beta-blockers (CYP2D6 Substrates):
- Carvedilol (Coreg, etc.)
- Metoprolol (Lopressor, etc.)
- Nebivolol (Bystolic)
- Propranolol (Inderal, etc.)
- Timolol (Blocadren, etc.)
PRECIPITANT DRUGS
Enzyme Inhibitors (CYP2D6):
- Abiraterone (Zytiga)
- Amiodarone (Cordarone, etc.)
- Cimetidine (Tagamet, etc.)
- Cinacalcet (Sensipar)
- Clobazam (Onfi)
- Diphenhydramine (Benadryl, etc.)
- Haloperidol (Haldol)
- Mirabegron (Myrbetriq)
- Propafenone (Rythmol, etc.)
- Propoxyphene*
- Quinidine (Quinidex)
- Ritonavir (Norvir)
- Terbinafine (Lamisil, etc.)
- Thioridazine (Mellaril)
* Propoxyphene (Darvon) was withdrawn from the US market.
Comment:
Inhibitors of CYP2D6 can increase the concentration of beta-blockers, potentially resulting in bradycardia, hypotension or heart failure. Rapid metabolizers of CYP2D6 (over 90% of the population) will be at the greatest risk. Note that because terbinafine has an extraordinarily long terminal half-life, the inhibitory effect of terbinafine on CYP2D6 may last for many weeks after terbinafine is discontinued.
Class 3: Assess Risk & Take Action if Necessary
- Consider Alternative:
- Cimetidine: Other acid suppressors are unlikely to interact. Consider using famotidine (Pepcid), nizatidine (Axid), ranitidine (Zantac), dexlansoprazole (Kapidex), esomeprazole (Nexium), omeprazole (Prilosec), lansoprazole (Prevacid), rabeprazole (Aciphex), or pantoprazole (Protonix).
- Beta-blocker: Select a beta-blocker that is not a CYP2D6 substrate such as atenolol (Tenormin) or nadolol (Corgard).
- Monitor:Monitor for altered beta-blocker effect if inhibitor is initiated, discontinued, or changed in dosage.