The generic name for Viagra is sildenafil, and sildenafil can usually be taken one tablet a week, but try not to take it too often. Sildenafil is a drug for the treatment of erectile dysfunction, if there is erectile dysfunction, the patient can be about an hour before sexual activity, take on demand the general recommended dose is one tablet, but the tolerance of each patient is different, some patients need to reduce the amount of the appropriate, if you take it once a week the impact is not very big, does not belong to the frequent use of drugs. And sildenafil’s metabolism is relatively fast, the drug will not be a long time in the body caused by the impact of the general 24 to 48 hours after taking the drug will gradually metabolized. When using the drug, pay attention to the person who is allergic to any component of the product is prohibited, taking any dosage form of nitrate patients are prohibited. Sildenafil medication must be guided by a doctor, the patient can not self-medicate at will, especially not frequent use of the drug.