OBJECT DRUGS

Phosphodiesterase Inhibitors:

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

PRECIPITANT DRUGS

Antidepressants:

• Fluvoxamine (Luvox, etc.)
• Nefazodone

Comment:

The phosphodiesterase inhibitors are metabolized by CYP3A4 and concurrent administration with CYP3A4 inhibitors 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:Sertraline (Zoloft), venlafaxine (Effexor), paroxetine (Paxil), citalopram (Celexa), and escitalopram (Lexapro) are not known to inhibit CYP3A4. Fluoxetine (Prozac) appears to be a weak CYP3A4 inhibitor.
• Monitor: Monitor for phosphodiesterase inhibitor toxicity including visual disturbances, hypotension, and syncope. Reduced dose of the phosphodiesterase inhibitor may be required.