23dideoxythymidine

23dideoxythymidine, commonly known as d4T or stavudine, is a synthetic nucleoside analog used primarily in the treatment of human immunodeficiency virus (HIV) infections. It was first synthesized in the late 1980s and later approved by regulatory agencies for medical use. As a thymidine analog, d4T functions as a chain terminator during viral DNA synthesis, inhibiting the replication of HIV and reducing viral load in infected individuals.

Stavudine is typically administered orally in the form of tablets or syrup and is often prescribed in combination with other antiretroviral drugs as part of highly active antiretroviral therapy (HAART). Its mechanism of action involves incorporation into the viral DNA by HIV reverse transcriptase, leading to premature chain termination and suppression of viral replication. While effective, d4T is associated with potential side effects, including peripheral neuropathy, lactic acidosis, and lipodystrophy, which have prompted its reduced use in modern treatment regimens.

Due to its toxicity profile, stavudine has largely been replaced by newer, more tolerable nucleoside reverse transcriptase inhibitors (NRTIs) such as zidovudine (AZT) or tenofovir. However, it remains relevant in certain clinical settings, particularly in resource-limited regions where cost and availability may influence treatment choices. Resistance mutations to d4T have been documented, necessitating careful monitoring and potential regimen adjustments in long-term therapy.

Clinical studies have demonstrated that stavudine can improve CD4 cell counts and reduce HIV-related morbidity, though its use is now generally restricted to specific patient populations under medical supervision. The drug’s pharmacokinetics involve rapid absorption and metabolism, with elimination primarily occurring through hepatic and renal pathways. As with all antiretroviral medications, adherence to treatment regimens is critical to achieving sustained virological suppression and minimizing the risk of drug resistance.