“Viagra, a type 5 phosphodiesterase inhibitor, is a first-line drug for the treatment of male erectile dysfunction with proven efficacy. Here’s a look at what the familiar and mysterious Viagra is all about. 1. How does Viagra work? It increases the concentration of cyclic guanosine monophosphate in penile cells by inhibiting the type 5 phosphodiesterase activity that degrades cyclic guanosine monophosphate, which leads to relaxation of penile smooth muscle and increased blood flow in the arteries of the penile corpus cavernosum, eventually leading to an erection; 2. Is there only one kind of Viagra? No, Viagra is the common name of a class of drugs, which includes sildenafil, vardenafil, tadalafil three; 3, the role of Viagra is only momentary? Not exactly, it depends on the half-life of the drug, in general, the half-life of sildenafil is 3.7 hours, vardenafil is 3.9 hours, tadalafil is 17.5 hours, so sildenafil and vardenafil belong to the short-acting class of preparations, tadalafil belongs to the long-acting class of preparations; that is to say, oral long-acting tadalafil can play an erectile role within 36 hours; 4, after taking Viagra immediately Can I get an erection immediately after taking Viagra? Not so, oral type 5 phosphodiesterase inhibitors must have sexual stimulation to play an erectile effect; 5, Viagra can be used in combination? In general, it is suitable for use alone, but for patients who do not have good results with one oral drug, a long-acting and a short-acting drug can be used in combination; 6, can Viagra be used in combination with drugs for premature ejaculation? Yes, in many cases, patients with erectile dysfunction have significant premature ejaculation, so they can take Viagra along with oral 5hydroxytryptamine reuptake inhibitors, such as dapoxetine, etc.; 7, which groups are suitable for oral Viagra treatment? Generally, adult men with erectile dysfunction can take Viagra treatment, and there is no age limit, especially for middle-aged and elderly people with “three high” performance; 8, what are the contraindications to oral Viagra? Generally in oral nitrates and a-blockers are not oral Viagra treatment, in order to avoid serious hypotension. 9.Is Viagra only taken temporarily? Not always, it can be taken as needed, for patients with “three highs” combined with erectile dysfunction can be individualized (sexually active, chronic disease treatment needs) long-term use of the drug, can be once a day, once a week or once a month, etc..