Which class of medications includes sildenafil, tadalafil, and vardenafil?

Which class of medications includes sildenafil, tadalafil, and vardenafil?

• A. Calcium channel blockers
• B. ACE inhibitors
• C. Phosphodiesterase type 5 inhibitors
• D. Antidepressants

Answer: (C)

These medications work by inhibiting phosphodiesterase type 5, which prevents the breakdown of cGMP in response to nitric oxide. During sexual stimulation, nitric oxide is released and raises cGMP levels, causing smooth muscle relaxation in the penile vessels and allowing increased blood flow to produce an erection. By blocking PDE5, sildenafil, tadalafil, and vardenafil amplify this normal NO-cGMP pathway, making it easier to obtain an erection with sexual arousal. This mechanism is distinct from the actions of calcium channel blockers, ACE inhibitors, or antidepressants, which operate through different targets and indications. A key safety point is that combining PDE5 inhibitors with nitrates can cause dangerous hypotension, and these drugs are metabolized by CYP3A4, leading to possible drug interactions.

These medications work by inhibiting phosphodiesterase type 5, which prevents the breakdown of cGMP in response to nitric oxide. During sexual stimulation, nitric oxide is released and raises cGMP levels, causing smooth muscle relaxation in the penile vessels and allowing increased blood flow to produce an erection. By blocking PDE5, sildenafil, tadalafil, and vardenafil amplify this normal NO-cGMP pathway, making it easier to obtain an erection with sexual arousal. This mechanism is distinct from the actions of calcium channel blockers, ACE inhibitors, or antidepressants, which operate through different targets and indications. A key safety point is that combining PDE5 inhibitors with nitrates can cause dangerous hypotension, and these drugs are metabolized by CYP3A4, leading to possible drug interactions.