Which drug is indicated for the treatment of HIV infections?

Zidovudine is a medication specifically indicated for the treatment of HIV infections. It belongs to a class of antiretroviral drugs known as nucleoside reverse transcriptase inhibitors (NRTIs). Zidovudine works by inhibiting the reverse transcriptase enzyme, which is essential for the replication of the HIV virus. By disrupting this process, Zidovudine helps to reduce the viral load in the body and maintains the immune system's function by preventing the virus from multiplying.

Other options listed are not used for the treatment of HIV. Docosanol is primarily used for the treatment of cold sores, while Acyclovir is an antiviral drug effective against herpes viruses, not HIV. Lamivudine is also an NRTI and is actually used to treat HIV, but in this context, Zidovudine is often one of the historical first-line therapies that are well-studied and recognized in control of HIV infection. In summary, Zidovudine's role as an antiretroviral agent for HIV treatment makes it the correct choice in this scenario.