Which complication is most associated with chloramphenicol and limits its use?

Which complication is most associated with chloramphenicol and limits its use?

• A. Allergic reactions
• B. Bone marrow suppression and aplastic anemia
• C. Significant gastrointestinal manifestations
• D. Photosensitivity

Answer: (B)

Chloramphenicol is limited by a serious hematologic toxicity: bone marrow suppression. There are two manifestations to understand. First, dose-dependent suppression of the bone marrow is common and usually reversible, causing decreases in red cells, white cells, and platelets. This can lead to anemia, infection risk from leukopenia, and bleeding tendencies from thrombocytopenia, but it often improves if the drug is stopped or the dose reduced.

More ominous is a rare, idiosyncratic aplastic anemia, which is not related to dose and can be irreversible and fatal. Because this outcome can occur unpredictably at any exposure level, it carries such gravity that it largely determines when chloramphenicol is used—typically only for life-threatening infections or when no safer alternatives exist. This toxicity is the reason its use is tightly restricted and patients on it require careful monitoring of blood counts.

Other side effects like gastrointestinal upset or photosensitivity do occur but are far less limiting than the potential for serious bone marrow damage.