-
Didanosine
- indication:For use, in combination with other antiretroviral agents, in the treatment of HIV-1 infection in adults.
- pharmacologypharmacology:
- mechanism: Didanosine (ddI) is metabolized intracellularly by a series of cellular enzymes to its active moiety, dideoxyadenosine triphosphate (ddATP), which inhibits the HIV reverse transcriptase enzyme competitively by competing with natural dATP. It also acts as a chain terminator by its incorporation into viral DNA as 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.
- toxicity: Side effects include pancreatitis, peripheral neuropathy, diarrhea, hyperuricemia and hepatic dysfunction
- absorprion: Rapidly absorbed (bioavailability 30-40%) with peak plasma concentrations appearing within 0.5 and 1.5 hrs.
- halflife: 30 minutes in plasma and more than 12 hours in intracellular environment.
- roouteelimination: Based on data from in vitro and animal studies, it is presumed that the metabolism of didanosine in man occurs by the same pathways responsible for the elimination of endogenous purines. Purines are eliminated by the kidneys.
- volumedistribution:
- clearance: