Epivir is one of the drugs used to fight infection with the human immunodeficiency virus (HIV), the deadly cause of AIDS. Doctors turn to Epivir as the infection gets worse. The drug is taken along with Retrovir, another HIV medication.

HIV does its damage by slowly destroying the immune system, eventually leaving the body defenseless against infections. Like other drugs for HIV, Epivir interferes with the virus's ability to reproduce. This staves off the collapse of the immune system.