Sildenafil

(sil den' a fil)

Molecule Info

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Indication & Dosage

Oral route
Erectile dysfunction
Adult: 50 mg about 1 hr before sexual intercourse. May adjust dose depending on penile response. Max: 100 mg/dose and not to be taken > once in 24 hr.
Elderly: >65 yr: Lower initial dose at 25 mg.

CrCl (ml/min) Dosage Recommendation
<30 Initially, 25 mg.

 

Hepatic impairment: Initially, 25 mg.

Special Populations: Patients with hepatic or renal impairment (creatinine clearance <30 mL/min): 25 mg.

Administration Should be taken with food.
Overdosage Should be managed by standard supportive care.
Contraindications Hypersensitivity. Patients concurrently or intermittently using organic nitrates in any form.
Special Precautions Caution when used in patients with anatomical deformation of penis or conditions that may predispose them to priapism (e.g. sickle cell anaemia, myeloma, or leukaemia). Mild, transient, dose-related impairment of colour discrimination (blue/green) may occur. Hepatic or severe renal impairment, bleeding disorders, active peptic ulceration, hypotension, recent history of stroke, MI, arrhythmias, unstable angina, heart failure or retinal disorders. May cause sudden loss or decrease in hearing.
Adverse Drug Reactions Headache, flushing, respiratory tract infection, angina pectoris, AV block, migraine, syncope, tachycardia, postural hypotension, MI, cerebral thrombosis, cardiac arrest, paraesthesia, tremor, depression, herpes simplex, skin ulcer, oesophagitis, abnormal LFT, rectal haemorrhage, hypoglycaemic reaction, arthritis, deafness, retinal vascular disease, photosensitivity, accidental fall.
Drug Interactions Inhibitors of CYP3A4 such as cimetidine and erythromycin are likely to reduce sildenafil clearance. CYP3A4 inducers such as rifampicin may decrease the plasma concentrations of sildenafil. Symptomatic hypotension when used with α-blockers. Plasma concentrations are increased by ritonavir.
Potentially Fatal: May potentiate hypotensive effects of of organic nitrates and nicorandil.

Food Interaction Concurrent admin with grapefruit juice may lead to increased plasma levels of sildenafil.
Pregnancy Category (US FDA) Category B: Either animal-reproduction studies have not demonstrated a foetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the 1st trimester (and there is no evidence of a risk in later trimesters).
Storage Oral: Store at 15-30°C.
Pharmacology Sildenafil inhibits phosphodiesterase type-5 (PDE5) which is responsible for cGMP degradation in the corpus cavernosum. Inhibition of PDE5 increases cGMP levels in the corpus cavernosum which results in smooth muscle relaxation and inflow of blood to the corpus cavernosum.
Absorption: Rapidly absorbed after oral admin. Bioavailability: about 40%.
Distribution: Widely distributed. Plasma protein binding: 96%.
Metabolism: Metabolised in the liver mainly by CYP3A4 and CYP2C9.
Excretion: Excreted as metabolites mainly in the faeces.
mph Class Drugs for Erectile Dysfunction
ATC Classification G04BE03 - sildenafil; Belongs to the class of drugs used in erectile dysfunction.

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Brand/Product Info


Total Products : 7       
Brand Name Manufacturer/Marketer Composition Dosage Form Pack Size & Price
ENEGRA 100 Beximco Pharmaceuticals Ltd Sildenafil Citrate INN 140.48mg eq. to Sildenafil 100mg Tablet 4's: 200.00 MRP
ENEGRA 50 Beximco Pharmaceuticals Ltd Sildenafil Citrate INN 70.24mg eq. to Sildenafil 50mg Tablet 4's: 120.00 MRP
Silagra 100 Incepta Pharmaceuticals Limited Sildenafil Citrate INN 140.48 mg equivalent to Sildenafil 100 mg Capsule 1x4's:MRP 200 Tk
Silagra 50 Incepta Pharmaceuticals Limited Sildenafil Citrate INN 70.24 mg equivalent to Sildenafil 50 mg Capsule 1x4's:MRP 120 Tk
VIGOREX 100 Square Pharmaceuticals Ltd. Sildenafil Citrate 100mg Tablet 1x4's: 200.60
VIGOREX 25 Square Pharmaceuticals Ltd. Sildenafil Citrate 25mg Tablet 1x4's: 80.24
VIGOREX 50 Square Pharmaceuticals Ltd. Sildenafil Citrate 50mg Tablet 1x4's: 120.40

Gen. MedInfo

Why is this medication prescribed?

Sildenafil (e.g. Viagra) is used to treat erectile dysfunction in men and belongs to a class of medications called phosphodiesterase inhibitors. It is used to improve the ability to exercise in adults with pulmonary arterial hypertension and should not be used in children. It treats erectile dysfunction by increasing blood flow to the penis during sexual stimulation. This increased blood flow can cause an erection. Sildenafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow easily.

If you are taking sildenafil to treat erectile dysfunction, you should know that it does not cure erectile dysfunction or increase sexual desire. Sildenafil does not prevent pregnancy or the spread of sexually transmitted diseases such as human immunodeficiency virus (HIV).

How should this medicine be used?

Sildenafil usually comes as a tablet to take by mouth.

If you are taking sildenafil to treat erectile dysfunction, follow your doctor's directions and the guidelines in this paragraph. Take sildenafil as needed before sexual activity. The best time to take sildenafil is about 1 hour before sexual activity, but you can take the medication any time from 4 hours to 30 minutes before sexual activity. Sildenafil usually should not be taken more than once every 24 hours. If you have certain health conditions or are taking certain medications, your doctor may tell you to take sildenafil less often. You can take sildenafil with or without food. However, if you take sildenafil with a high-fat meal, it will take longer for the medication to start to work.

If you are taking sildenafil to treat PAH, follow your doctor's directions and the guidelines in this paragraph. You will probably take sildenafil three times a day with or without food. Take sildenafil at around the same times every day, and space your doses about 4 to 6 hours apart.

Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take sildenafil exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Shake the liquid well for 10 seconds before each use to mix the medication evenly. Use the Oral   syringe provided with your medication to measure and take your dose. Follow the manufacturer's directions to use and clean the Oral   syringe. Do not mix the liquid with other medications or add anything to flavor the medication.

If you are taking sildenafil for erectile dysfunction, your doctor will probably start you on an average dose of sildenafil and increase or decrease your dose depending on your response to the medication. Tell your doctor if sildenafil is not working well or if you are experiencing side effects.

If you are taking sildenafil for PAH, you should know that sildenafil controls PAH but does not cure it. Continue to take sildenafil even if you feel well. Do not stop taking sildenafil without talking to your doctor.

What special precautions should I follow?

Before taking sildenafil (e.g. Viagra),
  • tell your Doctor if you are allergic to sildenafil or any other medications.
  • do not take sildenafil if you are taking or have recently taken nitrates such as isosorbide dinitrate, isosorbide mononitrate, and nitroglycerin. Nitrates come as tablets, sublingual tablets, sprays, patches, pastes, and ointments. Ask your doctor if you are not sure whether any of your medications contain nitrates.
  • do not take street drugs containing nitrates such as amyl nitrate and butyl nitrate while taking sildenafil.
  • tell your Doctor what prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Be sure to mention any of the following: alpha blockers such as alfuzosin, doxazosin, prazosin, tamsulosin, and terazosin; amlodipine; certain antifungals such as itraconazole and ketoconazole; anticoagulants such as warfarin; certain barbiturates such as butalbital and secobarbital; beta blockers such as atenolol, labetalol, metoprolol, nadolol, and propranolol; bosentan; cimetidine;efavirenz; erythromycin; HIV protease inhibitors including amprenavir, atazanavir, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, and tipranavir; nevirapine; other medications or devices to treat erectile dysfunction; medications for high blood pressure; certain medications for seizures including carbamazepine, phenobarbital, and phenytoin; rifabutin; and rifampin. Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with sildenafil, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
  • tell your doctor what herbal products you are taking or plan to take, especially St. John's wort.
  • tell your doctor if you smoke, if you have ever had an erection that lasted for several hours, and if you have recently lost a large amount of body fluids. This can happen if you are sick with fever, diarrhea, or vomiting; sweat a lot; or do not drink enough liquids. Also tell your doctor if you have or have ever had pulmonary veno-occlusive disease; a stomach ulcer; heart, kidney, or liver disease; a heart attack; an irregular heartbeat; a stroke; chest pain; high or low blood pressure; high cholesterol; a bleeding disorder; blood circulation problems;blood cell problems such as sickle cell anemia, multiple myeloma, or leukemia; conditions affecting the shape of the penis; or diabetes. Also tell your doctor if you or any of your family members have or have ever had an eye disease such as retinitis pigmentosa or if you have ever had sudden severe vision loss, especially if you were told that the vision loss was caused by a blockage of blood flow to the nerves that help you see.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking sildenafil, consult your doctor.
  • if you are having surgery, including dental surgery, tell your doctor or dentist that you are taking sildenafil.
  • if you are taking sildenafil to treat erectile dysfunction, tell your doctor if you have ever been advised by a health care professional to avoid sexual activity for medical reasons or if you have ever experienced chest pain during sexual activity. Sexual activity may be a strain on your heart, especially if you have heart disease. If you experience chest pain, dizziness, or nausea during sexual activity, consult your doctor immediately and avoid sexual activity until your doctor tells you otherwise.
  • tell all your health care providers that you are taking sildenafil. If you ever need emergency medical treatment for a heart problem, the health care providers who treat you will need to know when you last took sildenafil.
What special dietary instructions should I follow?

Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medicine.

What should I do if I forget a dose?

If you are taking sildenafil (Viagra) for erectile dysfunction, you are unlikely to miss a dose since this medication is taken as needed, not on a regular dosing schedule.

If you are taking sildenafil for PAH, take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What side effects can this medication cause?
Sildenafil may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
  • headache
  • heartburn
  • diarrhea
  • flushing
  • nosebleeds
  • difficulty falling asleep or staying asleep
  • numbness, burning, or tingling in the arms, hands, feet, or legs
  • muscle aches
  • changes in color vision
  • sensitivity to light
  • sudden severe loss of vision
  • blurred vision
  • sudden decrease or loss of hearing
  • ringing in ears
  • dizziness or lightheadedness
  • fainting
  • chest pain
  • worsening shortness of breath
  • erection that is painful or lasts longer than 4 hours
  • itching or burning during urination
  • rash
Some side effects can be serious. If you experience any of the following symptoms, consult your doctor immediately.

Some patients experienced a sudden loss of some or all of their vision after they took sildenafil or other medications that are similar to sildenafil. The vision loss was permanent in some cases. It is not known if the vision loss was caused by the medication. If you experience a sudden loss of vision while you are taking sildenafil, consult your doctor immediately. Do not take any more doses of sildenafil or similar medications such as tadalafil or vardenafil until you talk to your doctor.

There have been reports of heart attack, stroke, irregular heartbeat, bleeding in the brain or lungs, high blood pressure, and sudden death in men who took sildenafil for erectile dysfunction. Most, but not all, of these people had heart problems before taking sildenafil. It is not known whether these events were caused by sildenafil, sexual activity, heart disease, or a combination of these and other causes. Talk to your doctor about the risks of taking sildenafil.

Some patients experienced a sudden decrease or loss of hearing after they took sildenafil or other medications that are similar to sildenafil. The hearing loss usually involved only one ear and did not always improve when the medication was stopped. It is not known if the hearing loss was caused by the medication. If you experience a sudden loss of hearing, sometimes with ringing in the ears or dizziness, while you are taking sildenafil, consult your doctor immediately. If you are taking sildenafil for erectile dysfunction, do not take any more doses of sildenafil or similar medications such as tadalafil or vardenafil until you talk to your doctor. If you are taking sildenafil for PAH, do not stop taking your medication until you talk to your doctor.

Sildenafil (Viagra) may cause other side effects. Consult your doctor if you have any unusual problems while you are taking this medication.

What storage conditions are needed for this medicine?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store the tablets at room temperature and away from excess heat and moisture. Store the medication at room temperature or in a refrigerator, but do not freeze it. Throw away any unused medication after 30 days or any medication that is outdated/no longer needed.

 Ref: MedlinePlus, U.S. Natl. Library of Medicine


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