Key takeaways
Sildenafil (Revatio) and sildenafil (Viagra) are both medications that belong to the PDE-5 inhibitor class and contain the same active ingredient, sildenafil. They are used to treat different conditions: Revatio is FDA-approved for pulmonary arterial hypertension (PAH), while Viagra is FDA-approved for erectile dysfunction (ED). Revatio is taken three times a day in doses of 10 mg or 20 mg, whereas Viagra is taken as needed, typically 50 mg about an hour before sexual activity, with a maximum dose of 100 mg. Revatio is available in oral, liquid, and injection forms, while Viagra is only available as an oral tablet. Both medications are available as a lower-cost generic. Common side effects include headache, flushing, and indigestion. You should not take either medication with nitrates, like nitroglycerin or isosorbide. Doing so can lead to dangerously low blood pressure.
