Resistance to zidovudne develops due to:: (A) Mutation at reverse transcriptase, (B) Increased efflux of the drug from inside the cell, (C) Increased metabolism of the drug, (D) Decreased zidovudine 5 triphosphate formation
Answer is A. Zidovudine;It is a thymidine analogue (azidothymidine, AZT), the prototype NI. After phosphorylation in the host cell-zidovudine triphosphate selectively inhibits viral reverse transcriptase (RNA-dependent DNA polymerase) in preference to cellular DNA polymerase Resistance to AZT occurs by point mutations which alter reverse transcriptase enzyme. ESSENTIALS OF MEDICAL PHARMACOLOGY K.D.TRIPATHI SIXTH EDITION PAGE NO:770