It is perfectly fine to take Viagra once in a while. Viagra is the common name for a class of drugs called type 5 phosphodiesterase inhibitors, including sildenafil, vardenafil, and tadalafil. These drugs are currently the main drugs for the treatment of male erectile dysfunction, the overall side effects are small, high safety, occasional taking is perfectly fine. One of the ways to take these drugs is to take them on demand, i.e. orally about 30 minutes before sexual intercourse. It is important to emphasize that if you are taking nitrate drugs, such as isosorbide nitrate. These drugs are forbidden to be taken together with Viagra-type drugs, and taking them once in a while is an absolute contraindication.