Sildenafil: ildenafil, sold under the brand name Viagra among others, is a medication used to treat erectile dysfunction and pulmonary arterial hypertension. It is unclear if it is effective for treating sexual dysfunction in women. It is taken by mouth or by injection into a vein. Onset is typically within 20 minutes and lasts for about 2 hours.
Common side effects include headaches, heartburn, and flushed skin. Caution is advised in those with cardiovascular disease. Rare but serious side effects include a prolonged erection (priaprism) that can lead to damage to the penis, vision problems, and hearing loss. Sildenafil should not be taken by people on nitrates such as nitroglycerin (glycerin trinitrate), as this may result in a serious drop in blood pressure. Sildenafil should not be taken within four hours of taking an alpha one antagonist.
Sildenafil acts by blocking phosphodiesterase 5 (PDE5), an enzyme that promotes breakdown of cGMP, which regulates blood flow in the penis. It requires sexual arousal, however, to work. It also results in dilation of the blood vessels in the lungs.
Pfizer originally discovered the medication in 1989 while looking for a treatment for heart-related chest pain. It was approved for medical use in the United States and in the European Union in 1998. In 2017, it was the 217th most commonly prescribed medication in the United States, with more than two million prescriptions. In 2017, it became available as a generic medication after final patents by Pfizer expired. In the United Kingdom, it is available over the counter. Most of the Active Pharmaceutical Ingredient (API) in Sildenafil, Sildenafil citrate, is produced in Pfizer’s Ringaskiddy complex, County Cork, which is Pfizer’s largest production facility outside of the United States
Sildenafil is used to treat male sexual function problems (impotence or erectile dysfunction-ED). In combination with sexual stimulation, sildenafil works by increasing blood flow to the penis to help a man get and keep an erection.This drug does not protect against sexually transmitted diseases (such as HIV, hepatitis B, gonorrhea, syphilis). Practice “safe sex” such as using latex condoms. Consult your doctor or pharmacist for more details.
How to use Sildenafil Tablet
Read the Patient Information Leaflet provided by your pharmacist before you start taking sildenafil and each time you get a refill. If you have any questions, ask your doctor or pharmacist.
To treat erectile dysfunction-ED, take this drug by mouth as directed by your doctor, usually as needed. Take sildenafil at least 30 minutes, but no more than 4 hours, before sexual activity (1 hour before is the most effective). Do not take more than once daily.
A high-fat meal may delay how quickly the drug begins to work.
The dosage is based on your medical condition, response to treatment, and other medications you may be taking. Be sure to tell your doctor and pharmacist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).
Dizziness, headache, flushing, or stomach upset may occur. Vision changes such as increased sensitivity to light, blurred vision, or trouble telling blue and green colors apart may also occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.
To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.
Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
Sexual activity may put extra strain on your heart, especially if you have heart problems. If you have heart problems and experience any of these serious side effects while having sex, stop and get medical help right away: severe dizziness, fainting, chest/jaw/left arm pain, nausea.
Rarely, sudden decreased vision, including permanent blindness, in one or both eyes (NAION) may occur. If this serious problem occurs, stop taking sildenafil and get medical help right away. You have a slightly greater chance of developing NAION if you have heart disease, diabetes, high cholesterol, certain other eye problems (“crowded disk”), high blood pressure, if you are over 50, or if you smoke.
Rarely, a sudden decrease or loss of hearing, sometimes with ringing in the ears and dizziness, may occur. Stop taking sildenafil and get medical help right away if these effects occur.
In the rare event you have a painful or prolonged erection lasting 4 or more hours, stop using this drug and get medical help right away, or permanent problems could occur.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.