How long does sildenafil (Revatio) last?

The effects of sildenafil (Revatio) can [last for about 4 hours](https://pmc.ncbi.nlm.nih.gov/articles/PMC1994020/#:~:text=The%20effect%20peaks%20at%2060%20minutes%20and%20lasts%20as%20long%20as%204%20hours). During that time, it works to relax and widen the blood vessels between your heart and lungs. This helps the heart work less hard. Since these effects last about that long, take sildenafil (Revatio) 3 times a day, about [4 to 6 hours apart](https://www.ncbi.nlm.nih.gov/books/NBK558978/#:~:text=three%20times%20daily%2C-,4%C2%A0to%206%20hours%20apart.,-Injections%20are%20dosed). It's important to take the medication every day as prescribed. This helps it work the best it can to help your PAH from getting worse in the long run. Talk to your prescriber if you have other questions about how long the medication lasts.

Can a woman take sildenafil (Revatio)?

Yes. Women with pulmonary arterial hypertension (PAH) can take sildenafil (Revatio). [Studies](https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=3bb9363e-b28d-4019-8aae-539233dca214&type=display#section-13) included women and showed that the medication could work well for them. Sildenafil (Revatio) is approved for people of all genders with PAH.

Does sildenafil (Revatio) lower blood pressure?

Yes, sildenafil (Revatio) can [lower your blood pressure](https://www.goodrx.com/conditions/hypotension) for a short time after taking it. This can sometimes make you feel dizzy or weak. In [studies](https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=3bb9363e-b28d-4019-8aae-539233dca214&type=display#:~:text=Effects%20of%20REVATIO%20on%20Blood%20Pressure), adults with PAH who took this medication for a long time at a dose of 80 mg three times a day had a small drop in blood pressure, about 2 mmHg. This affected both the [top number (systolic) and bottom number (diastolic)](https://www.goodrx.com/conditions/hypertension/systolic-vs-diastolic-blood-pressure). Low blood pressure is more likely if you also take [other medications with the same effect](https://www.goodrx.com/conditions/hypotension/medications-that-cause-low-blood-pressure), like [blood pressure medications](https://www.goodrx.com/conditions/hypertension/choosing-your-blood-pressure-medication-what-type-is-best). If you feel dizzy or lightheaded after taking sildenafil (Revatio), sit down until you feel better. Hold onto something stable as you stand up. Tell your care team if this happens often or doesn't go away. They might adjust your treatment.

Does sildenafil (Revatio) make you drowsy?

No, feeling drowsy or sleepy isn't expected with sildenafil (Revatio). But this medication can lower your blood pressure. So if you feel very tired along with feeling dizzy and lightheaded, it could mean your [blood pressure is too low](https://www.goodrx.com/conditions/hypotension/when-to-go-to-the-er-for-low-blood-pressure). Talk to your prescriber if you feel sleepy often after starting sildenafil (Revatio). They can check out what might be going on.

sildenafil

Generic Revatio

Used for Pulmonary Hypertension

Sildenafil (Revatio) is used to treat pulmonary arterial hypertension or PAH (high blood pressure in the lungs) in people ages 1 year and older. It works as a phosphodiesterase 5 (PDE5) inhibitor to help improve your ability to exercise and slow PAH from getting worse. This medication is available as a tablet and oral suspension that you take by mouth. There's also an injection that's given through the vein in a hospital setting. In general, the dose is taken three times per day. Side effects include headache, flushing, and muscle pain. Sildenafil (Revatio) has both brand-name and generic versions.

Reviewed by:

Robert Chad Hakim, PharmD, BCCCP

Cydnee Ng, PharmD

Last reviewed on March 6, 2026

What is Sildenafil (Revatio)?

What is Sildenafil (Revatio) used for?

Pulmonary arterial hypertension or PAH (high blood pressure in the lungs)

How Sildenafil (Revatio) works

Sildenafil (Revatio) is a phosphodiesterase 5 (PDE5) inhibitor. It blocks a protein in the body called PDE5. This relaxes the blood vessels that go from your heart to your lungs.

When these blood vessels relax, more blood can flow through. This lowers the amount of work your heart needs to do to pump blood to your lungs to get oxygen for your body.

Are you looking for information on sildenafil (Viagra) for erectile dysfunction instead?

When does Sildenafil (Revatio) start working?Time passed since treatment started:

HOURS

DAYS

WEEKS

Initial effect

MONTHS

Full effect

Drug facts

Common Brands	Revatio
Drug Class	PDE5 inhibitor
Controlled Substance Classification	Not a controlled medication
Generic Status	Lower-cost generic available
Availability	Prescription only

Common Brands

Revatio

Drug Class

PDE5 inhibitor

Controlled Substance Classification

Not a controlled medication

Generic Status

Lower-cost generic available

Availability

Prescription only

More on Sildenafil (Revatio) essentials

An older woman is taking medication at home with the help of a nurse.
FG Trade/E+ via Getty Images

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

Written by Alyssa Billingsley, PharmD

Side effects of Sildenafil (Revatio)

The following side effects may get better over time as your body gets used to the medication. Let your healthcare provider know immediately if you continue to experience these symptoms or if they worsen over time.

Common Side Effects

Headaches (up to 49%)
Flushing (up to 16%)
Pain in arm or leg (15%)
Muscle pain (up to 14%)
Indigestion (up to 13%)
Back pain (up to 13%)
Diarrhea (up to 12%)

Less Common Side Effects

Nosebleed

Sildenafil (Revatio) serious side effects

Contact your healthcare provider immediately if you experience any of the following.

Low blood pressure: dizziness, lightheadedness, nausea, blurry vision, tiredness, fainting, fast heart rate, chest pain, confusion
Vision loss or other sudden vision changes
Hearing loss
Priapism: erection that lasts longer than 4 hours, pain during an erection

Source: DailyMed

The following Sildenafil (Revatio) side effects have also been reported

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Less common

Bladder pain

burning feeling in the chest or stomach

burning, crawling, itching, numbness, prickling, "pins and needles", or tingling feelings

cloudy or bloody urine

dizziness

increased frequency of urination

indigestion

pain on urination

stomach upset

tenderness in the stomach area

Rare

Abnormal vision

anxiety

behavior change similar to drunkenness

bleeding of the eye

blurred vision

bone pain

breast enlargement

chest pain

chills

cold sweats

confusion

convulsions (seizures)

cool and pale skin

deafness or hearing loss

decrease in amount of urine or the frequency of urination

decreased vision

difficulty in concentrating

dizziness or lightheadedness, especially when getting up suddenly from a lying or sitting position

double vision

drowsiness

dry eyes

dry mouth

dryness, redness, scaling, or peeling of the skin

excessive hunger

eye pain

fainting or faintness

fast, irregular, or pounding heartbeat

feeling of something in the eye

fever or chills

headache (severe or continuing)

increase in the size of the pupil

increased sweating

increased thirst

lower back or side pain

migraine headache

nausea (severe or continuing)

nervousness

nightmares

numbness of the hands

painful, swollen joints

prolonged, painful erection of penis

redness, burning, or swelling of the eyes

redness, itching, or tearing of the eyes

restless sleep

seeing shades of colors differently than before

sensitivity to light

shakiness

skin lesions with swelling

skin paleness

skin rash, hives, or itching

skin ulcers

slurred speech

sore throat

sudden weakness

swelling of the face, hands, feet, or lower legs

trouble breathing

twitching of the muscles

unusual feeling of burning or stinging of the skin

unusual tiredness or weakness

vision changes

vision loss, temporary

Incidence not known

Blindness

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

Aches or pains in the muscles

bloody nose

diarrhea

difficult or labored breathing

flushing

headache

pain or tenderness around the eyes and cheekbones

redness of the skin

sneezing

stomach discomfort following meals

stuffy or runny nose

trouble sleeping

unusually warm skin

Rare

Abdominal or stomach pain

abnormal dreams

anxiety

clumsiness or unsteadiness

cough

diarrhea or stomach cramps (severe or continuing)

difficulty in swallowing

ear pain

increased amount of saliva

increased skin sensitivity

lack of coordination

loss of bladder control

mental depression

nausea

numbness or tingling of the hands, legs, or feet

rectal bleeding

redness or irritation of the tongue

redness, soreness, swelling, or bleeding of the gums

ringing or buzzing in the ears

sensation of motion, usually whirling, either of one's self or of one's surroundings

sexual problems in men (continuing), including failure to experience a sexual orgasm

sleepiness

sores in the mouth and on the lips

tense muscles

trembling and shaking

vomiting

waking to urinate at night

worsening of asthma

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Pros and cons of Sildenafil (Revatio)

Pros

A first-choice option for treating PAH
Approved for people of all genders
Approved for children with PAH as young as 1 year old
Available as an oral liquid for people who have trouble swallowing pills

Cons

Can cause headaches and low blood pressure
Must take 3 times a day
Can't take if you also take nitrates for your heart
Not recommended if you also take erectile dysfunction medications

Pharmacist tips for Sildenafil (Revatio)

Take sildenafil (Revatio) 3 times a day every day so the medication works as best as it can to help your PAH. For example, you can take it in the morning, mid-afternoon, and in the evening. Separate your doses by a few hours, like 4 to 6 hours apart. Taking them too close together can put you at risk of side effects, like headache and low blood pressure.
You can take sildenafil (Revatio) with or without food.
Swallow sildenafil (Revatio) tablets whole. Don't break, crush, or chew the tablet. If you can't swallow them well, talk to your prescriber. They might be able to switch you to the oral suspension of medication.
Sildenafil (Revatio) can make your blood pressure drop and make you feel dizzy for a short time after taking it. Sit down if you feel dizzy. Then when you feel better, stand up slowly and hold onto something strong to help you up. If dizziness doesn't go away or if you have a racing heart, let your care team know.
Don't change your dose or stop taking sildenafil (Revatio) unless your prescriber tells you to. This is important even if you start to feel better. Stopping too soon can cause your symptoms to come back and can worsen your PAH.
Tell your healthcare team about all the medications you take or plan to take. This includes prescriptions, over-the-counter medications, vitamins, and supplements. Sildenafil (Revatio) can interact with many medications. Some are for blood pressure, enlarged prostate, or erectile dysfunction. Your care team can check for harmful interactions and adjust your medications if needed.
Don't take nitrate medications, such as nitroglycerin (Nitrostat), with sildenafil (Revatio). This can make your blood pressure drop to dangerously low levels.
Get medical help right away if you have sudden changes in vision or hearing while taking sildenafil (Revatio). Also get emergency help if you have an erection that lasts for more than 4 hours or is very painful. These problems can be serious and should get checked out.

More tips for the 10 mg/mL oral suspension of sildenafil (Revatio):

The pharmacy will prepare the oral suspension when you pick up the medication. They'll also give you a dosing cup, spoon, or oral syringe to help you measure out your dose.
Before taking a dose, shake the bottle well for at least 10 seconds. Use a medication dosing cup, spoon, or oral syringe to measure out your dose. Don't use household teaspoons. They might not be accurate, so you might take the wrong dose.
There are two options to store the oral suspension. You can keep it at room temperature (up to 86ºF). Or, you can put it in the refrigerator (though be sure not to let it freeze).
Once you get the oral suspension from the pharmacy, the medication is good for 60 days. The pharmacist usually writes the expiration date on the label on the bottle. Throw the medication away after this date, even if there's still medication left over.

Common questions about Revatio

No. Revatio and Viagra are brand-name medications that contain the same active ingredient, sildenafil. But they're used for different reasons. Viagra is FDA approved for erectile dysfunction in adult men. Revatio is approved to treat pulmonary arterial hypertension or PAH in adults and children ages 1 year and older. Because they're used for different things, their strengths and dosages are different. Don't take Revatio, Viagra, or generic sildenafil at the same time. This can put you at risk of side effects like very low blood pressure.

The effects of Revatio can last for about 4 hours. During that time, it works to relax and widen the blood vessels between your heart and lungs. This helps the heart work less hard. Since these effects last about that long, take Revatio 3 times a day, about 4 to 6 hours apart. It's important to take the medication every day as prescribed. This helps it work the best it can to help your PAH from getting worse in the long run. Talk to your prescriber if you have other questions about how long the medication lasts.

It can take up to 20 hours for most of Revatio to leave your body after one dose. This is based on the medication's half-life, which is the time it takes for half the amount to leave your body. Even though it can stay in your system for almost a day, it's important to take the medication as prescribed (3 times per day). This helps keep enough medication in your body to help with your PAH. Ask your prescriber if you have questions about how long Revatio stays in your system.

Take the amount of Revatio that your prescriber instructed you to. For adults with PAH, the typical dose is 20 mg by mouth three times a day. And for children 1 year and older with PAH, the typical dose is 10 mg or 20 mg by mouth three times a day (depending on weight). Your prescriber might recommend a different dose. This depends on how it works for your, side effects, and other medications you might be taking. Don't change your dose yourself unless your prescriber says it's okay to make sure it's safe. If you're not sure how much Revatio to take, ask your prescriber or pharmacist.

Yes. Women with pulmonary arterial hypertension (PAH) can take Revatio. Studies included women and showed that the medication could work well for them. Revatio is approved for people of all genders with PAH.

Yes, Revatio can lower your blood pressure for a short time after taking it. This can sometimes make you feel dizzy or weak. In studies, adults with PAH who took this medication for a long time at a dose of 80 mg three times a day had a small drop in blood pressure, about 2 mmHg. This affected both the top number (systolic) and bottom number (diastolic). Low blood pressure is more likely if you also take other medications with the same effect, like blood pressure medications. If you feel dizzy or lightheaded after taking Revatio, sit down until you feel better. Hold onto something stable as you stand up. Tell your care team if this happens often or doesn't go away. They might adjust your treatment.

Weight loss isn't a typical side effect of Revatio. If you notice unexplained weight loss, talk to your primary care provider. They can discuss with you about possible causes and ways to manage weight if needed.

No, feeling drowsy or sleepy isn't expected with Revatio. But this medication can lower your blood pressure. So if you feel very tired along with feeling dizzy and lightheaded, it could mean your blood pressure is too low. Talk to your prescriber if you feel sleepy often after starting Revatio. They can check out what might be going on.

Risks and warnings for Sildenafil (Revatio)

Sildenafil (Revatio) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.

Low blood pressure

Risk factors: Certain heart problems | Low fluids in the body (dehydration) | Low blood pressure at rest | Also taking erectile dysfunction medications | Also taking blood pressure medications | Also taking nitrates like nitroglycerin

Sildenafil (Revatio) can cause your blood pressure to drop. It can make you feel dizzy, tired, or lightheaded. This side effect is usually mild and doesn't last long.

Tell your prescriber and pharmacist about all the medications you take. You're at risk of having this side effect if you also take other medications that lower blood pressure. This includes blood pressure medications. You can't take sildenafil (Revatio) if you also take nitrates like nitroglycerin. This is because of the risk of a severe drop in blood pressure.

After you take sildenafil (Revatio), sit down for the first few minutes to help prevent dizziness. Change positions slowly. Get emergency help if you feel like you might pass out, feel confused, have a fast heartbeat, or have chest pain. These can be serious signs of very low blood pressure.

Not recommended for people with PVOD

Sildenafil (Revatio) isn't recommended if you have pulmonary vascular occlusive disease (PVOD). This is a rare condition that affects the blood flow between your lungs and heart.

Sildenafil (Revatio) hasn't been studied in people with PVOD. But it's possible that it can make this condition worse. Tell your care team if you have any shortness of breath, a cough that doesn't go away, tiredness, or chest pain. These could be signs of fluid buildup in your lungs, and your care team should check you for PVOD.

Nosebleeds

Risk factors: PAH due to connective tissue disease | Also taking the blood thinner called warfarin

Sildenafil (Revatio) can sometimes cause nosebleeds. This is more likely to happen if you take the blood thinner warfarin. Tell your care team if you start getting nosebleeds often. And get medical attention if you have a nosebleed that you can't stop.

Vision changes

Risk factors: History of eye problems, including a "crowded" optic disc

Although rare, reports of eye damage might be linked to taking PDE5 inhibitors like sildenafil (Revatio). This eye damage is called non-arteritic anterior ischemic optic neuropathy (NAION). It happens when there's poor blood flow to the nerves in the eye. Symptoms include sudden loss of vision in one eye, eye pain, and headache. It might lead to permanent vision loss if not treated.

Before you start sildenafil (Revatio), tell your prescriber about your full medical history. This medication isn't recommended for people with an eye problem called retinitis pigmentosa. The risk of this eye damage might also be higher if an eye specialist has told you that you have a "crowded" optic disc.

If you have sudden vision changes or lose vision in one or both eyes while taking sildenafil (Revatio), go to the emergency room or call an eye specialist right away. They can check out what's going on.

Hearing loss

Some people who took sildenafil (Revatio) reported hearing loss. This can sometimes happen with ringing in the ears (tinnitus) and dizziness. It isn't clear whether these effects are related to the medication or to other factors. Let your prescriber know if you notice changes in your hearing in one or both ears while taking sildenafil (Revatio).

Avoid use with other PDE5 inhibitors

Don't take sildenafil (Revatio) with other PDE5 inhibitors. This includes sildenafil (Viagra) for erectile dysfunction (ED). Others are tadalafil (Cialis), vardenafil (Levitra), and avanafil (Stendra). Taking more than one PDE5 inhibitor at the same time isn't recommended. It might raise your risk of side effects, like very low blood pressure, dizziness, headaches, and flushing.

Prolonged or painful erection (priapism)

Risk factors: Medical conditions that affect the penis | Sickle cell anemia | Multiple myeloma | Leukemia

Although rare, some people have had an erection that lasted more than 4 hours after taking a PDE5 inhibitor like sildenafil (Revatio). This can be very painful and might cause permanent damage to your penis if not treated in time. Get medical help right away if you have an erection that lasts longer than 4 hours or if you feel pain during an erection.

Sildenafil (Revatio) dosage

The average cost for 30 tablets of 20mg of Sildenafil (Revatio) is $10.05 with a free GoodRx coupon. This is 94.38% off the average retail price of $178.87.

Bottle of oral suspension

Dosage	Quantity	Price as low as	Price per unit
112ml of 10mg/ml	1 bottle	$37.95	$37.95

Tablet

Dosage	Quantity	Price as low as	Price per unit
20mg	30 tablets	$10.05	$0.34

Typical dosage for Sildenafil (Revatio)

Adults: The typical dose is 20 mg by mouth three times per day. Your prescriber can adjust the dose based on how well it's working and if you have side effects. The maximum dose is 80 mg by mouth three times per day.
Children ages 1 year and older: The dose depends on your child's weight.
- Weight of 44 lbs or less: The typical dose is 10 mg by mouth three times per day.
- Weight of 44 to 99 lbs: The typical dose is 20 mg by mouth three times per day.
- Weight of 99 lbs or more: The typical dose is 20 mg by mouth three times per day. If needed, the prescriber might adjust the dose. The maximum dose is 40 mg by mouth three times per day.

Sildenafil (Revatio) is also available as an injection that's given into a vein for people in the hospital who can't take it by mouth.

Interactions between Sildenafil (Revatio) and other drugs

Sildenafil (Revatio) may interact with certain medications or supplements. Always let your doctor and pharmacist know about any other medications or supplements (including prescribed and over-the-counter medications, vitamins, and dietary or herbal supplements) that you are currently taking. The list below does not include all possible drug interactions with Sildenafil (Revatio). Please note that only the generic name of each medication is listed below.

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

Amprenavir
Amyl Nitrite
Atazanavir
Boceprevir
Cobicistat
Darunavir
Erythrityl Tetranitrate
Fosamprenavir
Indinavir
Isosorbide Dinitrate
Isosorbide Mononitrate
Lopinavir
Molsidomine
Nelfinavir
Nitroglycerin
Nitroprusside
Pentaerythritol Tetranitrate
Propatyl Nitrate
Riociguat
Ritonavir
Saquinavir
Telaprevir
Tipranavir

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Cannabis
Ceritinib
Clarithromycin
Conivaptan
Dihydrocodeine
Duvelisib
Fluconazole
Fosnetupitant
Idelalisib
Itraconazole
Ivosidenib
Larotrectinib
Lefamulin
Lorlatinib
Lumacaftor
Nefazodone
Netupitant
Simeprevir
Telithromycin
Voriconazole

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

How much does Sildenafil (Revatio) cost?

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Revatio (brand)

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Sildenafil (Revatio) contraindications

Contraindications are specific health conditions or situations in which a person should not take a medication due to safety concerns. If you have any of the following conditions or if any of the following apply to you, let your healthcare provider know because Sildenafil (Revatio) will not be safe for you to take.