Although AZT does not prevent or cure AIDS, it does function in HIV treatment by inhibiting the virus’s ability to reproduce through interference in the transcription of RNA to DNA. The drug’s short-term benefits are generally believed to include a decrease in the number of other infections, an improvement in bodily T4 lymphocyte numbers, and an increase in body weight. Research is somewhat conflicted, however, and some medical experts believe that the adverse effects of long-term use of AZT should limit its use. Headache, weakness, nausea, bone marrow problems, and a decrease in some white blood cell counts are just a few of the adverse side effects that have been associated with the drug.