<prompt> Resistance to zidovudne develops due to:Mutation at reverse transcriptaseIncreased efflux of the drug from inside the cellIncreased metabolism of the drugDecreased zidovudine 5 triphosphate formation  <response>: 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 