Zalcitabine
Zalcitabine (2’-3’-Dideoxycytidine, ddC), is a derivative of the naturally existing deoxycytidine, made by replacing the hydroxyl group in position 3’ with a hydrogen. It is phosphorylated in the T cell into its active triphosphate form, ddCTP. This active metabolite works as a substrate for the reverse transcriptase, and also by incorporation into the viral DNA, hence terminating the chain elongation due to the missing hydroxyl group. Since zalcitabine is a reverse transcriptase inhibitor it possess activity only against retroviruses. It is used for the treatment of HIV infection only in combination with zidovudine.
Zalcitabine has a very high oral absorption rate, of over 80 %. The efficacy of zalcitabine is equivalent to that of zidovudine, but zalcitabine has more side effects. The most common side effect in the beginning of the treatment is nausea and headache. The more serious side effects are peripheral neuropathy, oesophagitis and pancreatitis.
References
- Harvey Stewart C. in Remington’s Pharmaceutical Sciences 18th edition: (ed. Gennard, Alfonso R.) Mack Publishing Company, 1990
- Rang H.P., Dale M.M., Ritter J.M.: Pharmacology, 3rd edition. Pearson Professional Ltd, 1995.