May 11, 2022

Sildenafil for Pulmonary Hypertension: Side Effects and Dosage

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

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

Sildenafil can 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 is also no cure. But sildenafil can help manage the disease and improve your quality of life.

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

In PH, the blood vessels that supply your lungs are tight and narrow. This is called 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 is a phosphodiesterase-5 (PDE5) inhibitor, which means 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 blood vessels. This causes vasodilation, which reduces resistance to blood flow and lowers blood pressure.

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

However, it can be used in children in some cases, according to the FDA.

In one statement 2012 (updated 2017), the FDA has recommended that sildenafil not be used to treat children (ages 1-17) with PH. The FDA states that there is a higher risk of death in children who take a high dose than in those who take a low dose.

As a result, some medical professionals refused to give the drug to children. However, the FDA has issued a follow-up statement in 2014 (updated 2016) clarifying their recommendation.

According to the statement, the FDA does not recommend never give the medicine 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 (more than 4 hours) in people with a penis
  • sudden loss of vision in one or both eyes
  • sudden hearing loss

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

Before taking sildenafil, talk to a doctor or other healthcare professional. They might make you change or stop taking certain medicines that can interact with sildenafil.

A doctor or other healthcare professional may also tell you to take certain precautions if you are at risk for certain side effects.

It is recommended that you avoid taking sildenafil if you:

  • have low blood pressure
  • take medications that lower blood pressure, such as nitrates
  • take antiretrovirals for HIV or AIDS
  • take Viagra
  • have recently had a heart attack or stroke
  • have severe heart or liver disease
  • have a condition that affects nerve function

It is not known if sildenafil can be used safely 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 may need higher and more frequent doses if you have severe PH.

A generic sildenafil 20mg tablet can cost $14 to $30. A 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 may cover some of the costs. There are also several ways to reduce your expenses:

  • Use coupons offered by prescription drug programs.
  • Check to see if the manufacturer offers patient assistance programs.
  • Check to see if you qualify for financial assistance from nonprofit or state programs.

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

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

Oxygen therapy

Oxygen therapy, or supplemental oxygen, can reduce the risk of death associated with PH. This is an oxygen tank and tube that delivers oxygen to your lungs.


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

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

Medications for PH can be prescribed alone or in combination.

There are also options for inhaled and intravenous medications.


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

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

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

You should avoid taking sildenafil if you suffer from low blood pressure or conditions involving the heart, liver or nervous system. Likewise, you should avoid using the drug if you are taking other drugs that lower blood pressure.

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

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