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Sildenafil

Brand names: Viagra, Revatio

Sildenafil treats erectile dysfunction (Viagra) and pulmonary arterial hypertension (Revatio).

Brand namesViagra, Revatio
Type of medicinePDE5 inhibitor
Prescription?Prescription
ImportantThis page is general information, not a prescription. Don't start, stop, or change a medicine without talking to your provider or pharmacist.

Overview

For ED, it helps an erection happen with sexual stimulation. It works for about 4 hours.

What it's used for

  • Erectile dysfunction
  • Pulmonary arterial hypertension

How to take it

  • For ED, take it about 1 hour before sex. Don't take it more than once a day.
  • A heavy, fatty meal can slow it down.

Your dose depends on your health and other medicines. Always follow your prescription label, and ask your pharmacist if anything is unclear.

Side effects

Common side effects

  • Headache
  • Flushing
  • Stuffy nose
  • Upset stomach
  • Blue-tinted vision
Call 911An erection that's painful or lasts more than 4 hours
Call 911Chest pain, fainting, or dizziness during sex
Call 911Sudden vision loss in one or both eyes
Call your provider todaySudden hearing loss or ringing in the ears

Warnings

  • Ask your provider if your heart is healthy enough for sex.
  • Only buy from a licensed pharmacy.

Other medicines, foods, and alcohol

  • Never take with nitrates (nitroglycerin, isosorbide) or riociguat; blood pressure can drop dangerously.
  • Alpha blockers (like tamsulosin) can add to dizziness.
  • Some antifungals, antibiotics, and HIV medicines raise its level.

Tell your provider and pharmacist about every medicine, vitamin, and supplement you take.

Pregnancy and breastfeeding

Revatio is used in pregnancy in some cases of pulmonary hypertension. Talk with your provider.

Missed doses, overdose, and storage

If you miss a dose

This medicine is often taken only when needed. If you take it on a schedule, take a missed dose when you remember, unless it's almost time for the next one. Don't double up.

If someone takes too much

Call Poison Control at 1-800-222-1222 or get help online at poison.org. Call 911 if the person collapses, has a seizure, has trouble breathing, or can't be woken.

Storing it

Store at room temperature, away from heat and moisture (not in the bathroom), and out of reach of children and pets.

Conditions it's used for

Sources

Last updated 2026-11-13.