Sildenafil relaxes muscles of the blood vessels and increases blood flow to particular areas of the body.

Sildenafil injection (Revatio) is used to treat pulmonary arterial hypertension and improve exercise capacity in men and women.

Another brand of sildenafil is Viagra, which is used to treat erectile dysfunction (impotence) in men. Revatio is used to treat PAH in both men and women.

Do not use sildenafil injection while also taking Viagra or other erectile dysfunction medications, unless your doctor tells you to.

Sildenafil injection may also be used for purposes not listed in this medication guide.

Some medicines can cause unwanted or dangerous effects when used with sildenafil. Tell your doctor about all your current medicines, especially riociguat (Adempas).

Do not use sildenafil if you are also using a nitrate drug for chest pain or heart problems, including nitroglycerin, isosorbide dinitrate, isosorbide mononitrate, and some recreational drugs such as "poppers." Using sildenafil with a nitrate medicine can cause a sudden and serious decrease in blood pressure.

Do not use sildenafil injection with Viagra similar medications such as avanafil (Stendra), tadalafil (Cialis) or vardenafil (Levitra). Tell your doctor about all medications you use for erectile dysfunction.

Get emergency medical help if you have ringing in your ears, sudden hearing loss, or sudden vision loss.

This medicine is injected into a vein through an IV. You may be shown how to use an IV at home. Do not self-inject sildenafil if you do not understand how to give the injection and properly dispose of used needles, IV tubing, and other items used to inject the medicine.

Sildenafil injection is usually given three times each day. Follow all directions on your prescription label. Do not use this medicine in larger or smaller amounts or for longer than recommended.

Prepare your dose only when you are ready to give an injection. Do not use if the medicine has changed colors or has particles in it. Call your pharmacist for new medicine.

Use a disposable needle only once, then throw away in a puncture-proof container (ask your pharmacist where you can get one and how to dispose of it). Keep this container out of the reach of children and pets.

Vomiting, diarrhea, or heavy sweating can cause you to become dehydrated. These conditions may cause very low blood pressure. Tell your doctor if you have a prolonged illness that causes diarrhea or vomiting.

Store at room temperature away from moisture and heat.

Usual Adult Dose for Erectile Dysfunction:

Initial dose: 50 mg orally once a day, as needed, 1 hour prior to sexual activity
Maintenance: 25 to 100 mg orally once a day, as needed, 1 hour prior to sexual activity

Comments: This drug may be taken anywhere from 30 minutes to 4 hours before sexual activity.

Use: Treatment of erectile dysfunction

Usual Adult Dose for Pulmonary Hypertension:

Revatio (R):
Oral:
-Initial dose: 5 or 20 mg orally three times a day, 4 to 6 hours apart
-Maximum dose: 20 mg orally three times a day

Injection:
-Initial dose: 2.5 or 10 mg IV bolus three times a day

Comments:
-No greater efficacy was achieved with oral doses higher than the maximum recommended dose.
-A 10 mg injection dose is predicted to provide pharmacological effect equivalent to the 20 mg oral dose.

Use: Treatment of PAH (WHO Group I) in adults to improve exercise ability and delay clinical worsening

Usual Geriatric Dose for Erectile Dysfunction:

Initial dose: 25 mg orally once a day 1 hour prior to sexual activity

Use: Treatment of erectile dysfunction

You should not use sildenafil injection if you are allergic to it, or:

• if you take other medicines to treat pulmonary arterial hypertension, such as riociguat (Adempas).

Do not use sildenafil injection if you are also taking a nitrate drug for chest pain or heart problems. This includes nitroglycerin, isosorbide dinitrate, and isosorbide mononitrate. Nitrates are also found in some recreational drugs such as amyl nitrate or nitrite ("poppers"). Using sildenafil with a nitrate medicine can cause a sudden and serious decrease in blood pressure.

To make sure sildenafil is safe for you, tell your doctor if you have ever had:

• heart disease or heart rhythm problems, angina (chest pain), coronary artery disease, circulation problems;

• a condition called pulmonary veno-occlusive disease;

• a heart attack, stroke, or congestive heart failure;

• high or low blood pressure;

• liver or kidney disease;

• a blood cell disorder such as sickle cell anemia, multiple myeloma, or leukemia;

• a bleeding disorder such as hemophilia;

• a stomach ulcer;

• retinitis pigmentosa (an inherited condition of the eye), or a history of vision loss;

• a physical deformity of the penis (such as Peyronie's disease).

Sildenafil can decrease blood flow to the optic nerve of the eye, causing sudden vision loss. This has occurred in a small number of people using sildenafil, most of whom also had heart disease, diabetes, high blood pressure, high cholesterol, or certain pre-existing eye problems, and in those who smoked or were over 50 years old. It is not clear whether sildenafil is the actual cause of vision loss.

This medicine is not expected to harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether sildenafil passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

Do not give this medication to anyone under 18 years old without medical advice.

Use the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not use extra medicine to make up the missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Avoid using other medicines to treat impotence without your doctor's advice.

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Stop using sildenafil and get emergency medical help if you have:

• heart attack symptoms--chest pain or pressure, pain spreading to your jaw or shoulder, nausea, sweating;

• vision changes or sudden vision loss; or

• erection is painful or lasts longer than 4 hours (prolonged erection can damage the penis).

Sildenafil may cause serious side effects. Call your doctor at once if you have:

• ringing in your ears, or sudden hearing loss;

• irregular heartbeat;

• swelling in your hands, ankles, or feet;

• shortness of breath; or

• a light-headed feeling, like you might pass out.

Common side effects of sildenafil may include:

• nosebleed;

• headache;

• upset stomach;

• flushing (warmth, redness, or tingly feeling);

• sleep problems (insomnia); or

• runny or stuffy nose.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Do not use Revatio with Viagra or similar medications such as avanafil (Stendra), tadalafil (Cialis) or vardenafil (Levitra). Tell your doctor about all medications you use for erectile dysfunction.

Tell your doctor about all your current medicines and any you start or stop using, especially:

• drugs to treat high blood pressure or a prostate disorder;

• an antibiotic--clarithromycin, erythromycin, or telithromycin;

• antifungal medicine--ketoconazole or itraconazole; or

• medicine to treat HIV/AIDS--atazanavir, indinavir, ritonavir, or saquinavir.

This list is not complete. Other drugs may interact with sildenafil, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.