## Core Concept
Zidovudine, also known as AZT (azidothymidine), is a nucleoside reverse transcriptase inhibitor (NRTI) used in the treatment of HIV/AIDS. Like all medications, it can cause side effects and complications. Understanding these is crucial for managing patients on this therapy.

## Why the Correct Answer is Right
The correct answer, **Bone marrow suppression**, is a well-documented side effect of zidovudine. This suppression can lead to anemia, neutropenia, and thrombocytopenia. The mechanism involves the drug's interference with the mitochondrial DNA synthesis, which affects rapidly dividing cells such as those in the bone marrow. This results in decreased production of blood cells.

## Why Each Wrong Option is Incorrect
- **Option A:** While gastrointestinal disturbances are common side effects of many drugs, they are not the most specific or severe complication associated with zidovudine compared to bone marrow suppression.
- **Option B:** Hepatotoxicity can occur with some antiretroviral drugs, but it is not the most directly associated complication with zidovudine compared to bone marrow suppression.
- **Option D:** Nephrotoxicity is more commonly associated with other classes of drugs, such as certain antiretroviral drugs like tenofovir, and is not a hallmark complication of zidovudine.

## Clinical Pearl / High-Yield Fact
A key clinical pearl is that **bone marrow suppression** leading to **anemia** and **neutropenia** is a dose-limiting side effect of zidovudine. This often necessitates dose adjustment or the use of hematopoietic growth factors like erythropoietin or granulocyte-colony stimulating factor (G-CSF).

## Correct Answer: C. Bone marrow suppression