Which of the following is a potential severe hematologic complication of oral acetazolamide?

• A. Aplastic anemia
• B. Rash
• C. Photosensitivity
• D. Nausea

Answer: (A)

Aplastic anemia arises from severe bone marrow suppression caused by acetazolamide, a sulfonamide-type carbonic anhydrase inhibitor. Although rare, this serious hematologic reaction leads to pancytopenia and a hypocellular marrow, producing fatigue from anemia, increased infections from leukopenia, and easy bleeding from thrombocytopenia. Discontinuing the drug and providing supportive care, including transfusions and infection management, are essential, with hematology input for potential marrow recovery or further treatment if needed.

Rash and photosensitivity are skin reactions common with sulfonamides, while nausea is a gastrointestinal side effect; neither reflects a hematologic crisis.