Sildenafil

Sildenafil helps men with erectile dysfunction get and maintain an erection for sexual intercourse. It usually starts to work within 30-60 minutes.

Sildenafil Overview

Updated: 

Sildenafil is a prescription medication used to treat erectile dysfunction (ED). Sildenafil is also used to treat adults with pulmonary arterial hypertension (PAH).

Sildenafil belongs to a group of drugs called PDE inhibitors. Sildenafil treats ED by increasing blood flow to the penis during sexual stimulation, which leads to an erection. Sildenafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow easily.

This medication comes in tablet form and is taken one hour before sexual activity if treating for ED. It is taken 3 times a day, 4-6 hours apart, if treating for PAH.

This medication also comes as an oral suspension (liquid) and in an injectable form to be given directly into a vein (IV) by a healthcare professional.

Common side effects include headache, facial flushing, and upset stomach.

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Uses of Sildenafil

Sildenafil is a prescription medication used to treat erectile dysfunction (ED) in adult males.

Sildenafil is also used to treat adults with pulmonary arterial hypertension, or PAH.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Sildenafil Brand Names

Sildenafil may be found in some form under the following brand names:

Sildenafil Drug Class

Sildenafil is part of the drug class:

Side Effects of Sildenafil

The most common side effects of sildenafil:

  • are headache
  • flushing of the face
  • upset stomach

Less common side effects that may occur are temporary changes in color vision (such as trouble telling the difference between blue and green objects or having a blue color tinge to them), eyes being more sensitive to light, or blurred vision.

In rare instances, men taking PDE5 inhibitors reported a sudden decrease or loss of vision in one or both eyes. It is not possible to determine whether these events are related directly to these medicines, to other factors such as high blood pressure or diabetes, or to a combination of these. If you experience sudden decrease or loss of vision, stop taking PDE5 inhibitors, including sildenafil, and call a doctor right away.

In rare instances, men have reported an erection that lasts many hours. You should call a doctor immediately if you ever have an erection that lasts more than 4 hours. If not treated right away, permanent damage to your penis could occur.

Sudden loss or decrease in hearing, sometimes with ringing in the ears and dizziness, has been rarely reported in people taking PDE5 inhibitors, including sildenafil. It is not possible to determine whether these events are related directly to the PDE5 inhibitors, to other diseases or medications, to other factors, or to a combination of factors. If you experience these symptoms, stop taking sildenafil and contact a doctor right away.

Heart attack, stroke, irregular heart beats, and death have been reported rarely in men taking sildenafil. Most, but not all, of these men had heart problems before taking this medicine. It is not possible to determine whether these events were directly related to sildenafil.

Sildenafil may cause other side effects besides those listed. If you want more information or develop any side effects or symptoms you are concerned about, talk to your doctor or pharmacist.

Sildenafil Interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take any of the following:

  • medicines called alpha blockers. These include Hytrin (terazosin HCl), Flomax (tamsulosin HCl), Cardura (doxazosin mesylate), Minipress (prazosin HCl) or Uroxatral (alfuzosin HCl). Alpha blockers are sometimes prescribed for prostate problems or high blood pressure. If sildenafil is taken with certain alpha blockers, your blood pressure could suddenly drop and you could get dizzy or faint.
  • other medicines to treat high blood pressure (hypertension)
  • medications that block a protein in the body (CYPA4) such as some macrolide antibiotics (clarithromycin, telithromycin), some HIV protease inhibitors (indinavir, nelfinavir, ritonavir, saquinavir), some HCV protease inhibitors (boceprevir, telaprevir), some azole antifungals (ketoconazole, itraconazole, posaconazole, voriconazole), conivaptan (Vaprisol), delaviridine (Rescriptor), and nefazadone (Serzor)
  • medications that increase the activity of the enzyme CYP3A4 such as carbamazepine (Tegretol, Equetro, Carbatrol), phenobarbital, phenytoin (Dilantin), rifampin (Rifadin), St John's wort, and nimodipine (Nimotop)
  • other medicines or treatments for ED.

Do not take sildenafil if you take any medicines called “nitrates.” Nitrates are commonly used to treat angina. Angina is a symptom of heart disease and can cause pain in your chest, jaw, or down your arm.

  • Medicines called nitrates include nitroglycerin that is found in tablets, sprays, ointments, pastes, or patches. Nitrates can also be found in other medicines such as isosorbide dinitrate or isosorbide mononitrate. Some recreational drugs called “poppers” also contain nitrates, such as amyl nitrite and butyl nitrite.
  • Ask your healthcare provider or pharmacist if you are not sure if any of your medicines are nitrates.

This is not a complete list of sildenafil drug interactions. Ask your doctor or pharmacist for more information.

Sildenafil Precautions

  • Sildenafil is not for newborns, children, or women.
  • Do not let anyone else take your sildenafil.
  • Sildenafil must be used only under a doctor's supervision.
  • There is potential risk of sexual activity in patients with cardiovascular risk factors. If you experience symptoms (chest pain, dizziness, nausea) upon initiation of sexual activity, it is advised to refrain from further sexual activity and discuss the episode with your doctor.
  • Sildenafil can cause your blood pressure to drop suddenly to an unsafe level if it is taken with certain other medicines. You could get dizzy, faint, or have a heart attack or stroke.
  • Tell all of your healthcare providers that you take sildenafil. If you need emergency medical care for a heart problem, it will be important for your healthcare provider to know when you last took sildenafil.
  • Seek immediate medical attention if sudden loss of vision occurs, which could be a sign of non-arteritic ischemic optic neuropathy (NAION).
  • Seek immediate medical attention if sudden decrease or loss of hearing occurs.

Do not take sildenafil if you:

  • take any medicines called “nitrates”. See "Drug Interactions" section.
  • use recreational drugs called “poppers” like amyl nitrite and butyl nitrite
  • are allergic to sildenafil or any of its ingredients. Symptoms of an allergic reaction may include:
    • rash
    • hives
    • swelling of the lips, tongue, or throat
    • difficulty breathing or swallowing
  • Call your healthcare provider or get help right away if you have any of the symptoms of an allergic reaction listed above.
  • Only your doctor can decide if sildenafil is right for you. Sildenafil can cause mild, temporary lowering of your blood pressure. You will need to have a thorough medical exam to diagnose your erectile dysfunction and to find out if you can safely take sildenafil alone or with your other medicines.

 

Sildenafil Food Interactions

Grapefruit and grapefruit juice may interact with sildenafil and lead to potentially dangerous effects. Discuss the use of grapefruit products with your doctor.

Inform MD

Be sure to tell your doctor if you:

  • have ever had any heart problems (e.g., angina, chest pain, heart failure, irregular heart beats, heart attack or narrowing of the aortic valve)
  • have ever had a stroke
  • have low or high blood pressure
  • have ever had severe vision loss
  • have a rare inherited eye disease called retinitis pigmentosa
  • have ever had any kidney problems
  • have ever had any liver problems
  • have ever had any blood problems, including sickle cell anemia or leukemia
  • are allergic to sildenafil or any of the other ingredients of sildenafil tablets
  • have a deformed penis, Peyronie's disease, or ever had an erection that lasted more than 4 hours
  • have stomach ulcers or any types of bleeding problems
  • are taking any other medicines
  • have sickle cell disease; sildenafil may cause serious complications if PAH is secondary to sickle cell disease

Sildenafil and Pregnancy

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

This medication falls into category B.

Sildenafil is not indicated for use in newborns, children, or women.

Sildenafil and Lactation

It is not known if sildenafil or its metabolites are excreted in human breast milk. Because many drugs pass into human milk, caution should be used when sildenafil is administered to a nursing woman.

Sildenafil Usage

This medication comes in tablet form and is taken one hour before sexual activity if treating for ED.

It is taken 3 times a day, 4-6 hours apart, if treating for pulmonary arterial hypertension (PAH).

This medication also comes as an oral suspension to be taken 3 times a day, 4-6 hours apart for the treatment of pulmonary arterial hypertension (PAH).

To prepare the oral solution:

  1. Tap the bottle to release the powder.
  2. Remove the cap.
  3. Accurately measure out 60 mL of water and pour the water into the bottle.
  4. Replace the cap and shake the bottle vigorously for a minimum of 30 seconds.
  5. Remove the cap.
  6. Accurately measure out another 30 mL of water and add this to the bottle. You should always add a total of 90 mL of water irrespective of the dose prescribed.
  7. Replace the cap and shake the bottle vigorously for a minimum of 30 seconds.
  8. Remove the cap.
  9. Press the bottle adaptor into the neck of the bottle. The adaptor is provided so that you can fill the oral syringe with medicine from the bottle. Replace the cap on the bottle.
  10. Write the expiration date of the constituted oral suspension on the bottle label (the expiration date of the constituted oral suspension is 30 days from the date of constitution).

This medication is available in an injectable form to be given directly into a vein (IV) by a healthcare professional.

Sildenafil Dosage

For the treatment of ED:

TABLETS: For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil may be taken anywhere from 4 hours to 0.5 hour before sexual activity. Your doctor may increase the dose to a maximum recommended dose of 100 mg or decreased it to 25 mg. Sildenafil is to be taken only once per day.

For the treatment of pulmonary arterial hypertension (PAH):

TABLETS and ORAL SOLUTION: The recommended dose of sildenafil is 20 mg three times a day. Take sildenafil doses 4–6 hours apart. Doses higher than 20 mg three times a day is not recommended.

INJECTABLE: The recommended dose is 10 mg (12.5 mL) given as an injection into the vein (IV) three times a day.

Sildenafil Overdose

If you take too much this medication, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.

If this medication is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention.

Other Requirements

Keep sildenafil out of the reach of children. Keep sildenafil in its original container. Store at room temperature away from excessive heat or moisture.