For more information, work with a member of our medical team who can order lab tests to look for any critical underlying problems. Common side effects include headache, facial flushing, indigestion, and dizziness. This medicine works best when you take it on an empty stomach an hour before sex. However, all medications come with risks. Viagra and alcohol: what are the rules? Stendra avanafil : This is an as-needed medication taken 30 minutes before sex and can last up to six hours.Viagra is the brand name for sildenafil, a medication for treating erectile dysfunction (ED). BlueChew and Hims offer chewable forms of these medications, which . Sildenafil (Viagra). This medicine works best when you take it on an empty stomach an hour before sex. The body takes longer to absorb it after a high-fat meal or . Sildenafil (Viagra, Revatio) is a moderately priced drug used to treat erection problems in men. It is also used to treat pulmonary arterial hypertension, a serious heart and lung .