Sildenafil is a drug that was created to treat high blood pressure and angina, or chest pain.

However, it’s best known for treating erectile dysfunction. When used for this purpose, its known by the brand name Viagra.

Sildenafil may also be used to treat pulmonary hypertension (PH). PH is a condition that involves high blood pressure in the vessels that bring blood to your lungs.

PH is a progressive disease that can lead to heart failure. There’s also no cure. But sildenafil can help manage the condition and improve your quality of life.

Sildenafil for PH is known by the brand name Revatio. Read on to learn about how it works, its side effects, and the recommended dosage.

In PH, the blood vessels that supply your lungs are tight and narrow. This is known as vasoconstriction.

When this happens, the resistance against blood flow increases. The result is high blood pressure.

Sildenafil works by causing vasodilation, or widening of your blood vessels. It’s a phosphodiesterase-5 (PDE5) inhibitor, meaning it decreases the activity of PDE5.

PDE5 is an enzyme that breaks down cyclic guanosine monophosphate (GMP). Cyclic GMP has a relaxing effect on your blood vessels.

By lowering your PDE5 levels, sildenafil allows more cyclic GMP to act on the blood vessels. This causes vasodilation, which lowers resistance against blood flow and lowers blood pressure.

The Food and Drug Administration (FDA) has only approved sildenafil to treat PH in adults. It’s not approved to treat the condition in children.

However, it may be used in children in certain cases, according to the FDA.

In a 2012 statement (updated as of 2017), the FDA recommended against using sildenafil to treat children (ages 1 to 17) with PH. The FDA states that there’s a higher risk of death in children who take a high dose than in those who take a low dose.

As a result, some healthcare professionals have refused to give children the drug. However, the FDA released a follow-up statement in 2014 (updated as of 2016) clarifying their recommendation.

According to the statement, the FDA doesn’t recommend never giving the drug to children. Instead, it may be used when the benefits outweigh the risks and there are limited alternatives for treatment.

The most common side effects associated with sildenafil include:

Other side effects may include:

The following side effects are rare but serious:

  • prolonged erection (lasting longer than 4 hours) in people with penises
  • sudden loss of vision in one or both eyes
  • sudden loss of hearing

It’s also possible to be allergic to sildenafil, but it’s not likely.

Before taking sildenafil, speak with a doctor or other healthcare professional. They might have you change or stop taking certain drugs that may interact with sildenafil.

A doctor or other healthcare professional may also have you take certain precautions if you’re at risk of certain side effects.

It’s recommended to avoid taking sildenafil if you:

  • have low blood pressure
  • are taking drugs that lower blood pressure, such as nitrates
  • are taking antiretroviral agents for HIV or AIDS
  • are taking Viagra
  • have recently had a heart attack or stroke
  • have a serious heart or liver condition
  • have a condition that affects nerve function

It’s unclear if sildenafil is safe to use during pregnancy or breastfeeding. Generally, it should only be used if the benefits outweigh the risks to the baby.

The usual sildenafil dosage for PH is 5 or 20 milligrams three times a day. Each dose should be taken 4 to 6 hours apart.

The ideal dosage depends on the severity of your PH. Therefore, you might need higher and more frequent doses if you have severe PH.

One 20-mg tablet of generic sildenafil can cost $14 to $30. One 20-mg tablet of brand name sildenafil (Revatio) can cost $58 or more.

The exact cost depends on several factors, including where you live and your pharmacy.

Your health insurance plan might cover some of the cost. There are also several ways to lower your expenses:

  • Use coupons offered by prescription drug programs.
  • Check whether the manufacturer offers patient assistance programs.
  • Check whether you’re eligible for financial assistance from nonprofit or state programs.

The goal of treatment is to manage your symptoms and slow down the progress of PH.

There are several options that can be used instead or in combination with sildenafil. Alternatives include:

Oxygen therapy

Oxygen therapy, or supplemental oxygen, can lower the risk of death associated with PH. It involves an oxygen tank and a tube, which deliver oxygen into your lungs.


In addition to sildenafil, other oral medications may be used to treat PH:

  • tadalafil (another PDE5 inhibitor)
  • bosentan
  • ambrisentan
  • macitentan
  • riociguat
  • beraprost
  • selexipag

Medications for PH might be prescribed alone or in combination.

There are also options for inhaled and intravenous drugs.


In severe cases, surgery for PH may be necessary. This includes the following procedures:

This option is typically used when medication fails to improve your condition.

Sildenafil is a prescription drug that’s used to treat PH. It works by widening the blood vessels to your lungs, which lowers the resistance against blood flow. This decreases your blood pressure.

You should avoid taking sildenafil if you have low blood pressure or conditions involving the heart, liver, or nervous system. Likewise, you should avoid using the drug if you’re taking other medications that lower blood pressure.

Common side effects of sildenafil include upset stomach, headache, skin flushing, and shortness of breath. To avoid serious side effects, be sure to follow a doctor’s or healthcare professional’s instructions for the dose amount and frequency.