Viagra (Sildenafil (Injection))

Viagra is the brand name of the prescription medicine sildenafil. It’s used to treat erectile dysfunction (trouble getting or keeping an erection) in men.

Another brand name of sildenafil, called Revatio, is used to treat pulmonary arterial hypertension (high blood pressure in the lungs) and improve exercise ability in men and women with this condition.

You shouldn’t take Viagra and Revatio together, unless your doctor tells you to do so.

Viagra is in a class of medicines known as phosphodiesterase (PDE) inhibitors. It works by increasing blood flow to the penis.

The U.S. Food and Drug Administration (FDA) approved this medicine in 1998. It’s marketed by Pfizer.

What is Viagra (Sildenafil (Injection)) used for?

  • Pulmonary Hypertension
  • Pulmonary Impairment
  • Pulmonary Heart or Vascular Disease
  • Thromboembolic Pulmonary Hypertension

warnings

What is the most important information I should know about Viagra (Sildenafil (Injection)) ?

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

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

Do not take sildenafil if you are also using 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"). Taking sildenafil with a nitrate medicine can cause a sudden and serious decrease in blood pressure.

Tell your doctor if you have ever had:

  • heart problems (chest pain, a heart rhythm disorder, heart attack);
  • high or low blood pressure;
  • blood circulation problems;
  • retinitis pigmentosa (an inherited condition of the eye);
  • blindness in one or both eyes;
  • bleeding problems;
  • a stomach ulcer;
  • pulmonary veno-occlusive disease (PVOD);
  • liver or kidney disease;
  • a blood cell disorder such as sickle cell anemia, multiple myeloma, or leukemia;
  • a physical deformity of the penis (such as Peyronie's disease); or
  • if you have been told you should not have sexual intercourse for health reasons.

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 taking 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.

Tell your doctor if you are pregnant. It is not known whether this medicine will harm an unborn baby. However, having pulmonary arterial hypertension (PAH) during pregnancy may cause complications such as heart failure, stroke, or medical problems in both mother and baby. The benefit of treating PAH with Revatio may outweigh any risks to the baby.

It may not be safe to breast-feed while using this medicine. Ask your doctor about any risk.

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

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Overall rating for Viagra (Sildenafil (Injection))

Side Effects

What are the side effects of Viagra (Sildenafil (Injection)) ?

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

Stop taking 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).

Call your doctor at once if you have:

  • severe shortness of breath, cough with foamy mucus;
  • ringing in your ears, or sudden hearing loss;
  • irregular heartbeat;
  • swelling in your hands, ankles, or feet;
  • a seizure; or (convulsions); or
  • a light-headed feeling, like you might pass out.

Common side effects may include:

  • flushing (warmth, redness, or tingly feeling);
  • headache, dizziness;
  • abnormal vision (blurred vision, changes in color vision)
  • runny or stuffy nose, nosebleeds;
  • sleep problems (insomnia);
  • muscle pain, back pain; or
  • upset stomach.

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.

Pregnancy & Breastfeeding

Can I take Viagra (Sildenafil (Injection)) if I’m pregnant or breastfeeding?

Tell your doctor if you are pregnant. It is not known whether this medicine will harm an unborn baby. However, having pulmonary arterial hypertension (PAH) during pregnancy may cause complications such as heart failure, stroke, or medical problems in both mother and baby. The benefit of treating PAH with Revatio may outweigh any risks to the baby.

It may not be safe to breast-feed while using this medicine. Ask your doctor about any risk.

Interactions

What drugs and food should I avoid while taking Viagra (Sildenafil (Injection)) ?

Drinking alcohol with this medicine can cause side effects.

Grapefruit may interact with sildenafil and lead to unwanted side effects. Avoid the use of grapefruit products.

Avoid using any other medicines to treat impotence, such as alprostadil or yohimbine, without first talking to your doctor.

Dosage Guidelines & Tips

How to take Viagra (Sildenafil (Injection)) ?

Use Viagra (Sildenafil (Injection)) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Revatio is usually taken three times each day, about 4 to 6 hours apart.

Viagra is usually taken only when needed, 30 minutes to 1 hour before sexual activity. You may take it up to 4 hours before sexual activity. Do not take Viagra more than once per day.

Shake the oral suspension (liquid) before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Viagra can help you have an erection when sexual stimulation occurs. An erection will not occur just by taking a pill. Follow your doctor's instructions.

During sexual activity, if you become dizzy or nauseated, or have pain, numbness, or tingling in your chest, arms, neck, or jaw, stop and call your doctor right away. You could be having a serious side effect of sildenafil.

Store at room temperature away from moisture and heat.

Since Viagra is used as needed, you are not likely to miss a dose.

If you miss a dose of Revatio, take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Overdose Signs

What happens if I overdose on Viagra (Sildenafil (Injection)) ?

What to Expect

Viagra usually starts to work within 30 to 60 minutes. You’ll need to be aroused for this medicine to work.

You should be able to achieve an erection between one and four hours after taking Viagra.

Your erection should go away after you have sex.

If Viagra doesn’t work for you, it may be due to a variety of factors, including the following:

  • You didn’t wait long enough or you waited too long after taking the medicine before having sex.
  • The dose wasn’t high enough.
  • You’re not sufficiently aroused.

Additional Dosage Information

Your dosage will depend on your medical condition, your overall health, and other factors.

For most men, the recommended dose is 50 milligrams (mg), taken as needed.

Secondary Uses

Sildenafil is sometimes used “off-label” to treat other medical conditions, including: