Drugs known to cause this condition inlcude:
- Alpha-Methyl dopa type: levodopa, methyldopa.
- Hapten type: Penicillins, cephalosporins.
- Quinidine type: quinidine.
- Others: mefenamic acid, salicylic acid, sulfonamides, Thiazide diuretics, antazoline, chlorpromazine, isoniazid, streptomycin, and Motrin. Drug-induced hemolytic anemia is most often associated with G6PD deficiency.
Once the diagnosis of hemolytic anemia is established drug intake must be excluded.
Coomb test differentiates the 3 main pathologic types.
alpha-Methyl dopa type: Coomb test is positive for IgG.
Hapten type: The diagnosis can be established by incubating the patient's serum with donor erythrocytes pre-incubated with penicillin. Deposition of IgG antibody will occur only in the presence of penicillin and can be detected with the Coombs' test.
Quinidine type: The diagnosis can be established in vitro by examining deposition of complement (C3) on donor erythrocytes by patient serum, which occurs only in the presence of the drug. The Coombs' test is used to detect complement deposition on the erythrocyte surface.