Viagra is an effective drug for treating male erectile dysfunction, but it targets sexual performance, not sexual arousal. There is limited evidence that Viagra may be beneficial for women with sexual dysfunction, but the trials have been small and the results inconsistent. Viagra is a prescription tablet that’s used to treat erectile dysfunction in adults. It comes in three strengths (25 mg, 50 mg, and 100 mg) and is taken as needed up to 4 hours before sexual. Sildenafil tablets (25 mg, 50 mg, 100 mg; Viagra, generic) and sildenafil oral film (25 mg, 50 mg, 75 mg, 100 mg; Vybrique) are used for ED. Sildenafil tablets (20 mg; Revatio, generic), sildenafil oral suspension (Revatio, generic), and sildenafil injection (Revatio, generic) are used for PAH. Viagra is one of the world's most counterfeited medicines. [90][91] According to a 2012 Pfizer study, around 80% of sites claiming to sell Viagra were selling counterfeits. “The little blue pill” known as Viagra is the world’s most popular erectile dysfunction medicine. It’s also the source of many inaccurate medical myths. Viagra (sildenafil) is a brand-name prescription drug that’s used to treat erectile dysfunction (ED). Learn about side effects, warnings, dosage, and more. Sildenafil (Viagra) is a tablet that's taken by mouth for erectile dysfunction (ED) in adults. It works as a phosphodiesterase-5 (PDE5) inhibitor to help people get an erection or keep an erection that lasts for sex. Erectile dysfunction is a condition where the penis does not harden and expand when a man is sexually excited, or when he cannot keep an erection. When a man is sexually stimulated, his body's normal response is to increase blood flow to his penis to produce an erection. But Viagra is sometimes considered the most effective ED treatment because it’s been used for many years and has a lot of research supporting its effectiveness. Oral medicines for ED usually work well and cause few side effects. The four main medicines taken by mouth for erectile dysfunction are: Avanafil (Stendra). Sildenafil (Viagra). Tadalafil (Cialis). Vardenafil. These medicines are called PDE5 inhibitors.