Which of the following is a known side effect of Zidovudine?

• A. Bone marrow suppression
• B. Hyperglycemia
• C. Hyponatremia
• D. Hepatotoxicity only in high dose

Answer: (A)

Zidovudine is an nucleoside reverse transcriptase inhibitor whose most characteristic toxicity is bone marrow suppression. It damages rapidly dividing hematopoietic cells, leading to anemia and neutropenia, which is why regular blood counts are essential during therapy and dose adjustments may be needed if cytopenias develop. This hematologic toxicity is the key adverse effect clinicians watch for with zidovudine. Other listed effects aren’t typical or defining for this drug: hyperglycemia is more associated with some metabolic therapies, hyponatremia isn’t a hallmark of zidovudine, and while hepatotoxicity can occur with antiretrovirals, it’s not the primary or most distinguishing toxicity of zidovudine (and not described as occurring only at high doses).