5 Things to Know About Sildenafil (Revatio) for Pulmonary Arterial Hypertension

Sildenafil, widely known as Viagra, is also a treatment for pulmonary arterial hypertension (PAH). PAH is a progressive condition that causes high blood pressure in the lungs. Under the brand name Revatio, sildenafil is used to help widen blood vessels in the lungs, which are narrowed with PAH. This can improve your ability to exercise and slow the progression of the condition.

Sildenafil is one of two phosphodiesterase 5 (PDE5) inhibitors that are FDA approved for PAH. Whether prescribed on its own or alongside other PAH treatments, sildenafil plays a vital role in managing this challenging condition. Here are five things — from benefits to side effects and more — you should know about sildenafil for PAH.

1. Sildenafil helps improve lung function and exercise capacity

There are two primary benefits of taking sildenafil for pulmonary arterial hypertension, or PAH. The medication helps improve exercise capacity and slows how quickly PAH worsens. 

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Here’s how sildenafil helps manage PAH:

• Improved lung function: Sildenafil works by relaxing the pulmonary arteries. This reduces resistance and lowers blood pressure in the lungs, which enhances overall lung function.

• Reduced strain on the heart: By improving blood flow to the lungs, sildenafil decreases the workload for the right side of the heart. This can help alleviate strain.

• Slowed progression: Sildenafil has been shown to slow clinical worsening of PAH. Clinical worsening typically involves at least one of the following outcomes: death, symptom worsening, hospitalization for PAH, or the need for more treatments.

• Enhanced exercise capacity: Clinical studies have shown significant improvement with sildenafil in the distance that people with PAH could walk during the 6-minute walk test. This test is a key measure of physical ability and endurance.

These combined benefits enable people with PAH to lead more active lives and have a greater ability to participate in everyday activities.

2. Sildenafil comes in multiple dosage forms, all of which are taken 3 times daily

Sildenafil is available in several dosage forms for managing PAH, including a tablet, a powder for oral suspension, and an oral liquid (Liqrev). Your pharmacist will mix the powder with liquid for you, if you choose that form. An IV injection is also available if you’re unable to take the oral forms for a period of time.

All of these forms are taken or administered 3 times a day. Most adults take 20 mg by mouth 3 times daily, while children’s dosages are based on body weight. Your dosage may be adjusted based on how you respond to and tolerate the medication.

Tadalafil (Adcirca, Alyq, Tadliq) is the other PDE5 inhibitor approved for PAH. It lasts longer in the body than sildenafil, so you only need to take it once a day. But tadalafil is only a treatment option for adults. Sildenafil, on the other hand, is approved for adults and kids ages 1 and older.

EXPERT PICKS: WHAT TO READ NEXT

• A guide to pulmonary arterial hypertension (PAH): In this article, experts break down the different symptoms and causes of PAH, along with the treatment options.

• How the treatments compare: There are many medications that can be used to help manage PAH. Learn about the different types of PAH medications and how they stack up.

• Sildenafil (Revatio) dosages: Explore this Revatio dosage guide for PAH, which covers typical dosages for children and adults, handling a missed dose, and what to do if you take too much.

3. Sildenafil has side effects and risks to be aware of

Like most medications, sildenafil can cause side effects. These side effects range from mild to serious. And many — including headaches, flushing, and nasal congestion — are the result of sildenafil causing blood vessels to widen. Nausea and drops in blood pressure are also possible. The higher your dosage, the greater the likelihood of experiencing these side effects is.

Here are a few tips for managing common sildenafil side effects:

• Limit triggers. Avoid alcohol, spicy foods, and hot beverages, which can worsen flushing. Alcohol can also worsen headaches and drops in blood pressure.

• Use a saline spray. Over-the-counter (OTC) saline nasal sprays can help clear congestion.

• Take your doses with food. If taking sildenafil on an empty stomach makes you nauseous, try taking it with a light meal or snack. But avoid taking your doses with large or fatty meals.

• Stand up slowly. Move slowly when standing up from a sitting or lying position to prevent dizziness from blood pressure changes.

• Talk to your healthcare team about OTC treatment options. If needed, your healthcare team can suggest safe OTC products for managing side effects. But be sure to steer clear of decongestants and nonsteroidal anti-inflammatory drugs (NSAIDs), since they can worsen PAH symptoms.

While rare, more serious side effects are also possible with sildenafil. This includes vision changes such as blurred vision, changes in how you see colors, or light sensitivity. Call your eye specialist right away if you notice any of these changes. 

There have also been reports of priapism (an erection lasting over 4 hours) with sildenafil. If you experience this side effect, seek emergency care.

4. Sildenafil can be combined with other PAH treatments

Sildenafil is often used as part of a combination therapy plan for PAH. It may be prescribed on its own or alongside one or more of these PAH medications:

• Endothelin receptor antagonist: Medications like ambrisentan (Letairis) and macitentan (Opsumit) block the effects of endothelin, a substance that constricts blood vessels.

• Prostacyclin analog or agonist: These medications help widen blood vessels and improve blood flow. They come as infusions, inhalations, and oral pills. Examples include treprostinil (Remodulin, Orenitram, Tyvaso) and selexipag (Uptravi).

• Activin signaling inhibitor: Sotatercept (Winrevair) is a newer PAH medication that can be added to your treatment plan if your symptoms progress. It blocks certain proteins that cause abnormal blood vessel growth and narrowing in the lungs, helping to reduce pressure.

Combination therapy may be necessary for more advanced PAH, or if one medication isn’t sufficiently managing your symptoms. Your healthcare team will modify your treatment plan based on the severity of your condition, your overall health, and your response to treatment.

5. Sildenafil can interact with many medications

Sildenafil can interact with various medications. For this reason, your healthcare team should be aware of any other prescription medications, OTC treatments, or supplements you’re taking.

Examples of medications that should be avoided or used with caution while taking sildenafil include:

• Nitrates: Nitrates like nitroglycerin, which are often used for chest pain, can cause hypotension (dangerously low blood pressure) when combined with sildenafil. This combination should be avoided.

• Alpha blockers: Alpha blockers are used to treat high blood pressure and prostate issues. When combined with sildenafil, these medications can increase the risk of low blood pressure, so dosage adjustments may be necessary. Examples of alpha blockers include tamsulosin (Flomax) and doxazosin (Cardura).

• Other PDE5 inhibitors: Taking sildenafil with medications in the same class, such as tadalafil, can heighten the risk of side effects. This combination isn’t recommended.

• Blood pressure medications: There’s a risk of excessive drops in blood pressure when sildenafil is combined with certain blood pressure medications. Combining sildenafil with one of these medications may require close monitoring. Examples include diuretics (water pills) and beta blockers.

This isn’t a complete list of medications that sildenafil can interact with. So make sure to provide your current medication list to your healthcare team. They can check for potential interactions before they become an issue.

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Written by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

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