A 30-Year-Old Man of Italian Ancestry Is Treated with High

A 30-year-old man of Italian ancestry is treated with high doses of a combination antibiotic for his chronic sinusitis.After 1 week of drug treatment, a dark brown discoloration of the urine is noted, and the hematocrit is found to be 32%.Haptoglobin is virtually undetectable.What is a likely mechanism for the patient's drug-induced anemia?

A) Galactose metabolism is inhibited.
B) There is not enough ribose to support DNA replication.
C) Red blood cells produce too much apo-hemoglobin.
D) Glutathione reduction by the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) is impaired.
E) The reduced form of nicotinamide adenine dinucleotide (NADH) oxidase overproduces oxygen radicals.