Stendra 50 mg is a medication that treats erectile dysfunction. This condition affects people who are unable to get and keep an erection during sexual intercourse. You can take these tablets with a glass of water as directed, about 15 to 30 minutes before sexual activity. A large part why Stendra, the brand name for avanafil, is so expensive is that there is not yet a low-cost, generic version of it on the market. Rather, you can only buy the brand name.