What Happens When You Take Sildenafil Tablet

What Happens When You Take Sildenafil Tablet

Describe sildenafil.
The blood vessel muscles are relaxed by sildenafil, which also enhances blood flow to specific body parts.

Erectile dysfunction (impotence) in men is treated with sildenafil sold as Viagra.

Revatio is a different brand of sildenafil that is used to treat pulmonary arterial hypertension and enhance exercise tolerance in both men and women.


If you also take nitrate medications for chest discomfort or cardiac issues, such as nitroglycerin, isosorbide dinitrate, isosorbide mononitrate, or some recreational substances like “poppers,” you should avoid using sildenafil. A fast and significant drop in blood pressure can occur when sildenafil and nitrate medications are taken together.

When used with sildenafil, several medications can have adverse or severe effects. Inform your physician about all of your current medications, particularly riociguat (Adempas). Never combine sildenafil with riociguat.

If your erection hurts or lasts more than four hours, call your doctor or get emergency medical help. Priapism, or an extended erection, can harm the penis.

If you experience sudden visual loss, stop taking sildenafil and seek emergency medical attention.

Prior to using this medication

In the event that you have an allergy to sildenafil or:

  • if you take riociguat or any other pulmonary arterial hypertension medications (Adempas).

If you are also taking a nitrate medication for heart issues or chest pain, avoid using this medication. This comprises isosorbide dinitrate, mononitrate, and nitroglycerin. Additionally, some recreational drugs like amyl nitrate and nitrite include nitrates (“poppers”). A fast and significant drop in blood pressure can occur when sildenafil and nitrate medications are taken together.

Inform your physician of any of the following to ensure that sildenafil is safe for you:

  • 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.

A sudden loss of vision may result from sildenafil’s ability to reduce blood flow to the optic nerve of the eye. A limited percentage of sildenafil users have experienced this, and the majority of them also had heart disease, diabetes, high blood pressure, high cholesterol, or certain pre-existing eye problems. Smokers and individuals over 50 years old were also more likely to have this. It is unclear if this medication is the root of the visual loss.

It is unlikely that this medication will hurt an unborn child. If you are pregnant or want to become pregnant, let your doctor know. Without seeing their doctor, women with pulmonary arterial hypertension should not discontinue taking sildenafil.

It is unknown if sildenafil enters breast milk or if it can be harmful to a nursing infant.


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

How should I take sildenafil?

Take sildenafil exactly as it was prescribed for you. Follow all directions on your prescription label and read all medication guides or instruction sheets.

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.

What happens if I miss a dose?

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.

What happens if I overdose?

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

What to avoid

Drinking alcohol with sildenafil 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.

Sildenafil side effects

Get emergency medical help if you have signs of an allergic reaction to sildenafil: 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;
  • erection is painful or lasts longer than 4 hours (prolonged erection can damage the penis);
  • ringing in your ears, or sudden hearing loss;
  • irregular heartbeat;
  • swelling in your hands, ankles, or feet;
  • shortness of breath;

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use sildenafil only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.