what exactly does viagra do?

If you’re looking for a less costly Viagra, you might want to ask your doctor about sildenafil. It’s the active ingredient in both branded Viagra and the drug Revatio, which is a lower dose than Viagra and approved to treat pulmonary arterial hypertension. 

The important difference: Generic Revatio is available for a fraction of the cost. 

“Generic Revatio is considerably less expensive, and it is the same drug as Viagra with the same safety and effectiveness,” says Bradley Anawalt, M.D., an endocrinologist and professor of medicine at the University of Washington in Seattle who chairs the Endocrine Society’s Hormone Health Network.

At a lower dose, sildenafil is approved to treat pulmonary arterial hypertension—the higher dose is reserved for treating erectile dysfunction (ED). Anawalt explains that there’s a chance your insurance might not cover it to treat ED. Still, if your doctor says it’s okay for you to use and you end up paying out-of-pocket, you can still get the generic for a lot less than Viagra.

According to price-comparison website GoodRx.com, generic Revatio will cost you as little as $0.70 per pill, depending on where you fill your prescription. That’s compared with more than $50 per pill for Viagra.  

And while generic Revatio is available only in a 20-mg strength—Viagra comes in 25-, 50-, and 100-mg tabs—not to worry: Your doctor can prescribe the most appropriate equivalent dose. “The 5-mg difference between sildenafil and the lowest dose of Viagra could easily be made up by taking an extra half pill, if needed,” says Consumer Reports’ chief medical adviser, Marvin M. Lipman, M.D. 

“Most patients benefit from taking a 50 to 100 mg dose,” explains Anawalt. “So, your doctor might recommend taking three to five tabs of sildenafil. That’s still far less expensive than one Viagra pill.” 

If you’re holding out for a generic version of branded Viagra, you won’t have to wait much longer. Teva Pharmaceuticals plans to release its generic of the “little blue pill” as early as December. 

In 2010, Pfizer, the maker of both Revatio and Viagra, sued Teva for patent infringement, or trying to introduce a generic version several years before Pfizer’s patent for Viagra was set to expire. Under a confidential settlement reached in 2013, Teva will have to pay Pfizer a royalty for a license to produce the generic, according to statements by both companies. 

Before rushing to try Viagra and other ED drugs, the American Urological Association, in conjunction with the Choosing Wisely campaign, recommends first ruling out and addressing underlying conditions that could cause ED.

CR medical consultants say that erection problems can be an early warning sign of heart disease, high blood pressure, or diabetes. Depression and relationship problems can also cause or worsen ED. CR Best Buy Drugs recommends you review your medications with your doctor or pharmacist because antidepressants, blood pressure medicines, heartburn drugs, common pain relievers, and many other drugs can cause ED as a side effect. 

If other conditions and medications aren’t the culprit, consider nondrug treatments. “Regular exercise and a healthy diet to lose weight are good first steps,” says Anawalt. “As are quitting smoking and limiting your alcohol intake.”

A 2011 review published in JAMA Internal Medicine found an association between lifestyle changes and improved ED symptoms.

Though ED drugs are effective, our medical experts warn that they should be used cautiously because they can cause potentially serious side effects. The risks may include an increased chance of heart attack or stroke among men already at risk of such events—including those with coronary disease—as well as fertility problems and worsened sleep apnea. In some men, the drugs may also cause temporary vision or hearing problems. 

You should not take ED drugs if you take a nitrate medicine, such as nitroglycerin pills, for heart problems. The combination can cause a  dangerous drop in blood pressure.

Editor’s Note: These materials were made possible by a grant from the state Attorney General Consumer and Prescriber Education Grant Program, which is funded by a multistate settlement of consumer fraud claims regarding the marketing of the prescription drug Neurontin (gabapentin).