The M184V mutation: what it does, how to prevent it, and what to do with it when it's there.

The M184V mutation is selected by lamivudine (3TC) and emtricitabine (FTC) and is a common mutation in HIV-infected patients. Virus with the M184V mutation has a high level of resistance to 3TC and FTC but has been shown to have favorable effects on the susceptibility of some other NRTIs and can delay clinical and immunologic progression by decreasing viral fitness. While it is always better not to have any drug resistance so that 3TC and FTC are available as active antiretroviral agents, it is important to take advantage of the beneficial effects of the M184V mutation when it is present.