Taken alone, Viagra won’t hurt your heart. But don’t take it if you’re already taking nitrates for heart health, Dr. Montague says.

Viagra was originally intended to treat angina (chest pain), which it does well — just no better than other medications. Stiffer erections were a side effect.

“Here’s a drug that not only treats angina and is good for the heart, but it works on the penis when other medications don’t,” he says.

Like nitrates, it helps dilate blood vessels constricted by coronary artery disease.

But it also similarly lowers blood pressure.

If you take the two medications together, your blood pressure could drop too low, putting you at risk for a heart attack.