Question

In patients with glucose-6-phosphate dehydrogenase deficiency (G-6-PD deficiency), hemolysis may be induced by the following EXCEPT

• A. Primaquine
• B. Nitrofurantoin
• C. Tetracycline
• D. Chloramphenicol

Hint:

Three of these are on the classic "oxidant drug" list for G6PD deficiency -- one is not.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks which drug is safe (does not trigger hemolysis) in G6PD deficiency, while the other three are recognized oxidant triggers.

Step 2: Key Concept or Approach:
G6PD deficiency impairs the pentose phosphate pathway, reducing the red cell's supply of NADPH and therefore reduced glutathione. Without enough reduced glutathione, red cells cannot neutralize oxidant stress, and hemoglobin denatures into Heinz bodies, leading to acute hemolysis when the patient is exposed to certain oxidant drugs, infections, or fava beans. Recognizing the classic list of oxidant drugs -- antimalarials like primaquine, nitrofurans, sulfonamides, and chloramphenicol -- versus drugs considered safe, such as tetracyclines, is a standard exam point.

Step 3: Working Through the Options:
Primaquine is the classic prototype oxidant drug that precipitates hemolysis in G6PD-deficient patients and is the reason for screening before antimalarial treatment. Nitrofurantoin is a well-established oxidant trigger, commonly tested alongside primaquine and sulfonamides. Tetracycline is not associated with oxidant hemolysis in G6PD deficiency and is considered safe to use, which is why it is the correct answer to "EXCEPT." Chloramphenicol is classically included among drugs that can precipitate hemolysis in G6PD deficiency and is grouped with the unsafe drugs in standard references.

Step 4: Conclusion:
The correct answer is tetracycline, the one drug among the choices that does not induce hemolysis in G6PD deficiency.