OBJECT DRUGS

Phosphodiesterase Inhibitors:

• Avanafil (Stendra)
• Sildenafil (Viagra, etc.)
• Tadalafil (Cialis, etc.)
• Vardenafil (Levitra, etc.)

PRECIPITANT DRUGS

Calcium Channel Blockers:

• Diltiazem (Cardizem, etc.)
• Verapamil (Isoptin, etc.)

Comment:

The phosphodiesterase inhibitors appear to be metabolized by CYP3A4 and concurrent administration with CYP3A4 inhibitors such as diltiazem and verapamil could produce increased plasma concentrations. Increased side effects may occur during coadministered with CYP3A4 inhibitors.

Class 3: Assess Risk & Take Action if Necessary

• Consider Alternative: Calcium channel blockers other than diltiazem and verapamil are unlikely to inhibit the metabolism of sildenafil. However, other calcium channel blockers may produce increased hypotensive effects when used with phosphodiesterase inhibitors.
• Monitor: Monitor for phosphodiesterase inhibitor toxicity including visual disturbances, hypotension, and syncope. Reduced dose of the phosphodiesterase inhibitor may be required.