Sildenafil: How It Works, Uses, and What to Know

What is sildenafil?

Sildenafil is an FDA-approved medication used to treat erectile dysfunction. It belongs to a class of drugs called PDE5 inhibitors, which work by increasing blood flow to the penis during sexual stimulation. It does not cause erections on its own — arousal is still required.

How sildenafil works

During sexual stimulation, sildenafil helps relax blood vessels in the penis, allowing increased blood flow. Most men take it about 30–60 minutes before sexual activity. Effects typically last about 4–6 hours, though individual response varies.

A clinician determines the appropriate dose based on your health history, other medications, and cardiovascular status.

Who may sildenafil be appropriate for?

Sildenafil may be appropriate for men with erectile dysfunction when a licensed clinician determines it is safe. It is not appropriate for everyone — particularly those taking nitrates for heart conditions, certain blood pressure medications, or with specific cardiovascular risks.

A private clinical evaluation helps determine whether sildenafil or another approach is right for you.

Common side effects and safety

Common side effects include headache, flushing, nasal congestion, and upset stomach. Serious but rare side effects can occur. Sildenafil should never be combined with nitrate medications.

Always disclose your full medication list and health history to your clinician. This page is educational — not prescribing guidance.

Sources

• FDA — Sildenafil Prescribing Information

Related guides

• Erectile dysfunction guide
• Tadalafil overview
• Compare sildenafil and tadalafil