Want to discuss your treatment options? This medicine also works best when you take it an hour before sex on an empty stomach. Some medications should not be taken with sildenafil. What should I do if I forget a dose? You should only be treated with one of these products at a time. Your doctor or other health care professional can recommend one for you based on these factors, other health conditions you have and any other medicines you take.written by Felix Team. Viagra is a prescription medication –– you’ll need to talk to a healthcare provider before you begin taking Viagra. While Viagra is safe and effective . No, you should not take Viagra if you don’t have ED. Viagra is a prescription medication that can have serious side effects. And it’s approved only to treat ED, not to be used. The safest way to get a prescription for Viagra is from your doctor. You can even do this over a telehealth call (on the phone or computer) in many cases, although for your first .