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Sildenafil (By injection)

Sildenafil (sil-DEN-a-fil)

Treats pulmonary arterial hypertension (high blood pressure in the lungs).

Brand Name(s):


There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. You should not receive it if you had an allergic reaction to sildenafil.

How to Use This Medicine:


  • Your doctor will prescribe your dose and schedule. This medicine is given through a needle placed in a vein.
  • A nurse or other health provider will give you this medicine.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Do not use this medicine if you also use riociguat or a nitrate medicine. Do not take other medicines that contain sildenafil or similar medicines, such as tadalafil or vardenafil.
  • Some medicines can affect how sildenafil works. Tell your doctor if you are using any of the following:
    • Amlodipine, bosentan, doxazosin, itraconazole, ketoconazole, ritonavir
    • Medicine for high blood pressure

Warnings While Using This Medicine:

  • Tell your doctor if you are pregnant or breastfeeding, or if you have kidney disease, liver disease, pulmonary veno-occlusive disease, diabetes, bleeding problems, leukemia, multiple myeloma, sickle cell anemia, a stomach ulcer, or eye problems. Tell your doctor if you have heart disease, heart failure, high cholesterol, or high or low blood pressure. Also tell your doctor if you smoke.
  • Tell any doctor who treats you that you take sildenafil.
  • This medicine may cause the following problems:
    • Low blood pressure (especially if taken with other medicines that lower blood pressure)
    • Heart problems
    • Painful or prolonged erection
    • Vision or hearing problems

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Chest pain, trouble breathing, sudden or severe headache
  • Fast, slow, pounding, or uneven heartbeat
  • Lightheadedness, fainting
  • Painful erection or an erection that lasts longer than 4 hours
  • Sudden loss of vision
  • Sudden decrease in hearing or hearing loss, ringing in the ears, dizziness

If you notice these less serious side effects, talk with your doctor:

  • Headache
  • Nosebleeds
  • Stuffy or runny nose
  • Upset stomach
  • Warmth or redness in your face, neck, arms, or upper chest

If you notice other side effects that you think are caused by this medicine, tell your doctor

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

Last Updated: 2/4/2020

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites.

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