This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy, Subject name: Pharmacology
Which of the following is most common side effect of zidovudine? 
Select and explain. 
A. Anemia, B. Peripheral neuropathy, C. Lactic acidosis, D. All
A: Anemia
Answer: A: Anemia 
Explanation: 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 Adverse effects Toxicity is mainly due to paial inhibition of cellular DNA polymerase. Anaemia and neutropenia are the most impoant and dose-related adverse effects. Nausea, anorexia, abdominal pain, headache, insomnia and myalgia are common at the sta of therapy but diminish later. Myopathy, lactic acidosis, hepatomegaly, convulsions and encephalopathy are infrequent. ESSENTIALS OF MEDICAL PHARMACOLOGY K.D.TRIPATHI SIXTH EDITION PAGE NO:770,771