Zidovudine, a structural analog of thymidine, inhibits the activity of HIV-1 reverse transcriptase (RT) both by competing with the natural substrate dGTP and by its incorporation into viral DNA.
Zidovudine is a nucleoside reverse transcriptase inhibitor (NRTI) with activity against Human Immunodeficiency Virus Type 1 (HIV-1). Zidovudine is phosphorylated to active metabolites that compete for incorporation into viral DNA. They inhibit the HIV reverse transcriptase enzyme competitively and act as a chain terminator of DNA synthesis. The lack of a 3'-OH group in the incorporated nucleoside analogue prevents the formation of the 5' to 3' phosphodiester linkage essential for DNA chain elongation, and therefore, the viral DNA growth is terminated.
Hepatic. Metabolized by glucuronide conjugation to major, inactive metabolite, 3_-azido-3_-deoxy-5_- O-beta-D-glucopyranuronosylthymidine (GZDV).
Symptoms of overdose include fatigue, headache, nausea, and vomiting. LD50 is 3084 mg/kg (orally in mice).