Generic Name: sildenafil (oral) (sil DEN a fil)
Brand Names: Revatio, Viagra
What is sildenafil?
Sildenafil relaxes muscles and increases blood flow to particular areas of the body.
Sildenafil under the name Viagra is used to treat erectile dysfunction (impotence) in men. Another brand of sildenafil is Revatio, which is used to treat pulmonary arterial hypertension and improve exercise capacity in men and women.
Do not take Viagra while also taking Revatio, unless your doctor tells you to.
Sildenafil may also be used for purposes not listed in this medication guide.
What is the most important information I should know about sildenafil?
Do not take sildenafil if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin (Nitrostat, Nitrolingual, Nitro-Dur, Nitro-Bid, and others), isosorbide dinitrate (Dilatrate-SR, Isordil, Sorbitrate), and isosorbide mononitrate (Imdur, ISMO, Monoket). 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. 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. Do not take sildenafil more than once a day. Allow 24 hours to pass between doses. Contact your doctor or seek emergency medical attention if your erection is painful or lasts longer than 4 hours. A prolonged erection (priapism) can damage the penis.
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 smoke or are over 50 years old. It is not clear whether sildenafil is the actual cause of vision loss.
Stop using sildenafil and get emergency medical help if you have sudden vision loss.
What should I discuss with my healthcare provider before taking sildenafil?
Do not take sildenafil if you are also using a nitrate drug for chest pain or heart problems. This includes nitroglycerin (Nitrostat, Nitrolingual, Nitro-Dur, Nitro-Bid, and others), isosorbide dinitrate (Dilatrate-SR, Isordil, Sorbitrate), and isosorbide mononitrate (Imdur, ISMO, Monoket). 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.
To make sure you can safely take sildenafil, tell your doctor if you have any of these other conditions:
heart disease or heart rhythm problems;
a recent history (in the past 6 months) of a heart attack, stroke, or congestive heart failure;
high or low blood pressure;
coronary artery disease;
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);
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 smoke or are over 50 years old. It is not clear whether sildenafil is the actual cause of vision loss. Stop using sildenafil and get emergency medical help if you have sudden vision loss. FDA pregnancy category B: This medication is not expected to be harmful to an unborn baby. Do not use sildenafil without telling your doctor if you are pregnant or plan to become pregnant during treatment. It is not known if sildenafil passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.
How should I take sildenafil?
Take exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.
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.
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.
See also: Sildenafil dosage (in more detail)
What happens if I miss a dose?
Viagra is used as needed, so you are not likely to be on a dosing schedule.
If you miss a dose of Revatio, take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. Overdose symptoms may include chest pain, nausea, irregular heartbeat, and feeling light-headed or fainting.
What should I avoid while taking sildenafil?
Drinking alcohol can increase certain side effects of sildenafil. Avoid using other medicines to treat impotence, such as alprostadil (Caverject, Muse, Edex) or yohimbine (Yocon, Yodoxin, others), without first talking to your doctor.
Sildenafil side effects
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. 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. Stop using sildenafil and call your doctor at once if you have a serious side effect such as:
sudden vision loss;
ringing in your ears, or sudden hearing loss;
chest pain or heavy feeling, pain spreading to the arm or shoulder, nausea, sweating, general ill feeling;
irregular heartbeat;
swelling in your hands, ankles, or feet;
shortness of breath;
vision changes;
feeling light-headed, fainting; or
- penis erection that is painful or lasts 4 hours or longer.
Less serious side effects may include:
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.
Sildenafil Dosing Information
Usual Adult Dose for Erectile Dysfunction:
Initial (oral): 50 mg orally administered as needed 1 hour prior to anticipated sexual activity. A maximum of one dose per day is recommended.
Maintenance (oral): 25 to 100 mg orally as needed 30 minutes to 4 hours prior to anticipated sexual activity. A maximum of one dose per day is recommended.
Usual Adult Dose for Pulmonary Hypertension:
20 mg orally three times a day taken at least 4 to 6 hours apart
or
10 mg (corresponding to 12.5 mL) administered as an intravenous bolus injection three times a day. A 10 mg dose of the injection is predicted to provide pharmacological effect of sildenafil and its N-desmethyl metabolite equivalent to that of a 20 mg oral dose. The injection is for the continued treatment of patients with pulmonary arterial hypertension (PAH) who are currently prescribed oral sildenafil and who are temporarily unable to take oral medication.
Usual Geriatric Dose for Erectile Dysfunction:
25 mg orally as needed 1 hour prior to anticipated sexual activity.
Usual Pediatric Dose for Pulmonary Hypertension:
Safety and effectiveness of sildenafil in pediatric pulmonary hypertension patients have not been established. Limited pediatric information exists; most pediatric literature consists of case reports or small studies; further studies are needed.
Neonates: Note: A wide range of doses and interpatient variability has been reported; careful dose titration is necessary.
Pulmonary hypertension: Reported range: 0.5 to 3 mg/kg/dose orally every 6 to 12 hours; the largest study was a double-blind, randomized, placebo-controlled trial and used an initial dose of 3 mg/kg/dose every 6 hours in 31 patients; earlier studies used 0.3 to 2 mg/kg/dose every 6-24 hours; duration not established.
Pulmonary hypertension, facilitation of inhaled nitric oxide wean: 0.3 mg/kg/dose orally given once 70 to 90 minutes prior to inhaled nitric oxide discontinuation was used in three patients. Multiple dose therapy in neonates and infants has been reported consisting of 0.22 to 0.47 mg/kg/dose every 6 hours (average duration: 28 days) to facilitate weaning from inhaled nitric oxide in patients who previously failed; duration not established.
Older than 1 yr:
Pulmonary hypertension:
Initial dose: 0.25 to 0.5 mg/kg orally every 4 to 8 hours, increase if needed and if tolerated to 1 mg/kg/dose every 4 to 8 hours; doses as high as 2 mg/kg/dose every 4 hours have been used in several case reports; a wide range of doses has been reported, duration not established. A retrospective trial of 25 patients with chronic lung disease reported treatment duration of 28 to 950 days (median: 241 days).
Pulmonary hypertension, facilitation of inhaled nitric oxide wean (in patients who have not previously failed inhaled nitric oxide wean): Single dose: 0.4 mg/kg/dose (range: 0.3 to 0.5 mg/kg/dose) given once 60 minutes prior to inhaled nitric oxide discontinuation was used in 15 patients (median age: 5.6 months).
What other drugs will affect sildenafil?
Do not take sildenafil with similar medications such as tadalafil (Cialis) or vardenafil (Levitra).
Before taking sildenafil, tell your doctor about all other medications you use for erectile dysfunction, or if you are using any of the following medications:
bosentan (Tracleer);
cimetidine (Tagamet);
conivaptan (Vaprisol);
imatinib (Gleevec);
isoniazid (for treating tuberculosis);
rifampin (Rifadin, Rimactane Rifater, Rifamate);
an antidepressant such as nefazodone;
an antibiotic such as clarithromycin (Biaxin), dalfopristin/quinupristin (Synercid), erythromycin (E.E.S., EryPed, Ery-Tab, Erythrocin, Pediazole), or telithromycin (Ketek);
antifungal medication such as itraconazole (Sporanox), ketoconazole (Nizoral), miconazole (Oravig), or voriconazole (Vfend);
heart or blood pressure medication such as diltiazem (Cardizem, Dilacor, Tiazac), doxazosin (Cardura), nicardipine (Cardene), quinidine (Quin-G), or verapamil (Calan, Covera, Isoptin, Verelan); or
HIV/AIDS medicine such as atazanavir (Reyataz), delavirdine (Rescriptor), fosamprenavir (Lexiva), indinavir (Crixivan), nelfinavir (Viracept), saquinavir (Invirase), or ritonavir (Norvir, Kaletra).
This list is not complete and other drugs may interact with sildenafil. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.
More sildenafil resources
- Sildenafil Side Effects (in more detail)
- Sildenafil Dosage
- Sildenafil Use in Pregnancy & Breastfeeding
- Sildenafil Drug Interactions
- Sildenafil Support Group
- 53 Reviews for Sildenafil - Add your own review/rating
- sildenafil Advanced Consumer (Micromedex) - Includes Dosage Information
- Sildenafil MedFacts Consumer Leaflet (Wolters Kluwer)
- Revatio Prescribing Information (FDA)
- Revatio Consumer Overview
- Sildenafil Citrate Monograph (AHFS DI)
- Viagra Prescribing Information (FDA)
- Viagra MedFacts Consumer Leaflet (Wolters Kluwer)
- Viagra Consumer Overview
Compare sildenafil with other medications
- Erectile Dysfunction
- Pulmonary Arterial Hypertension
- Sexual Dysfunction, SSRI Induced
Where can I get more information?
- Your pharmacist can provide more information about sildenafil.
See also: sildenafil side effects (in more detail)
