Often, these are prescribed for chest pain called angina. It might work longer if you have mild to moderate erectile dysfunction. That’s not to say there aren’t just as many illegitimate sites. This boosts blood flow and helps you get an erection from sexual activity. However, some states require a live video consultation. This medication is taken with or without food an hour before sex. These are commonly prescribed for an enlarged prostate or male pattern baldness.Missed dose. Overdose. Talk with your doctor. Q&A. Drug Images. Viagra (sildenafil) is a prescription drug that’s used to treat erectile dysfunction (ED). The drug comes as a tablet you’ll take. Still, if your doctor says it’s okay for you to use and you end up paying out-of-pocket, you can still get the generic for a lot less than Viagra. According to price-comparison site Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors. They enhance the effects of a chemical the body makes that relaxes muscles in the penis, called nitric oxide. This boosts blood flow and helps you get an erection from sexual activity. How oral medicines differ.