Which of the following NRTIs requires monitoring for myelosuppression?

Zidovudine is the NRTI that requires monitoring for myelosuppression. Myelosuppression refers to the reduction in the production of blood cells, which can lead to conditions like anemia and neutropenia. Zidovudine, particularly, is known for its potential to cause bone marrow suppression, and as a result, regular blood count monitoring is essential for patients taking this medication. This is key in managing and mitigating the risk of complications associated with low blood cell counts, especially in individuals who may already have a compromised immune system due to HIV.

Other NRTIs listed do not typically require such close monitoring for myelosuppression. Didanosine, Abacavir, and Lamivudine have different side effect profiles, and while they may have other adverse effects, they are not significantly associated with harmful impacts on bone marrow function in the same way that Zidovudine is. Understanding these distinctions is essential when managing HIV treatment and ensuring patient safety.