Viagra is one of the most well-known drugs in the world, used to treat erectile dysfunction, or ED, and impotence. Sildenafil is the active ingredient in Viagra. It relaxes muscles and blood vessels in the penis for better blood flow, making it easier for a man to develop an erection. Take Viagra within 60 minutes of sexual activity to make it easier to become erect. Note that common side effects include temporary changes in vision and flushing.

Common use
The main component of Viagra is Sildenafil Citrate.Sildenafil Citrate affects the response to sexual stimulation. It acts by enhancing smooth muscle relaxation using nitric oxide, a chemical that is normally released in response to sexual stimulation. This smooth muscle relaxation allows increased blood flow into certain areas of the penis, which leads to an erection.Sildenafil Citrate is applied for the treatment of erectile dysfunction (impotence) in men and pulmonary arterial hypertension.Sildenafil Citrate may also be used for other purposes not listed above.

Dosage and direction
Usually, the recommended dose is 50 mg. It is taken approximately 0,5-1 hour before sexual activity. Do not take Viagra more than once a day.A high-fat meal may delay the time of the effect of this drug.Try not to eat grapefruit or drink grapefruit juice while you are being treated with Sildenafil Citrate.
 
Precautions
Before you start taking Sildenafil Citrate, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies.Aged people may be more sensitive to the side effects of the drug.
 
Contraindications
Viagra is contraindicated in patients taking another medicine to treat impotence or using a nitrate drug for chest pain or heart problems.This medicine should not be taken by women and children as well as in patients with a known hypersensitivity to any component of the tablet.
 
Possible side effect
The most common side effects are headache, flushing, heartburn, stomach upset, nasal stuffiness, lightheadedness, dizziness or diarrhea.A serious allergic reaction to this drug is very rare, but seek immediate medical help if it occurs.Many people using this medicine do not have serious side effects.In case you notice any side effects not listed above, contact your doctor or pharmacist.
 
Drug interaction
This drug should not be used with nitrates and recreational drugs called "poppers" containing amyl or butyl nitrite; alpha-blocker medications; other medications for impotence; high blood pressure medicines, etc.Consult your doctor or pharmacist for more details.
 
Missed dose
Viagra is used as needed, so you are unlikely to be on a dosing schedule.
 
Overdose
If you think you have used too much of this medicine seek emergency medical attention right away. The symptoms of overdose usually include chest pain, nausea, irregular heartbeat, and feeling light-headed or fainting.
 
Storage
Store your medicines at room temperature between 68-77 degrees F (20-25 degrees C) away from light and moisture. Do not store the drugs in the bathroom. Keep all drugs away from the reach of children and pets.

Disclaimer
We provide only general information about medications which does not cover all directions, possible drug integrations, or precautions. Information at the site cannot be used for self-treatment and self-diagnosis. Any specific instructions for a particular patient should be agreed with your health care adviser or doctor in charge of the case. We disclaim the reliability of this information and the mistakes it could contain. We are not responsible for any direct, indirect, special, or other indirect damage as a result of any use of the information on this site and also for consequences of self-treatment.