SINCE the first report of drug-induced hemolytic anemia produced by stibophen,1 the list has been expanded to include 16 other drugs and chemical compounds.2
This group of hemolytic anemias has been classified as "immune" because to become antigenic the drug must combine with a macromolecule in the serum, thus forming a drug-antidrug complex.3 This complex attaches to the red blood cell (RBC) membrane by an unknown mechanism and leads to RBC destruction either by activation of complement or by binding of active C3 to the RBC surface, with subsequent recognition by the macrophages and destruction in the reticuloendothelial system.4
Several drugs have been reported to produce hemolysis without binding complement.5-7 In these cases, RBC destruction is probably due to coating of RBCs by immunoglobulins.
In the present case, an oral antihypertensive drug that is a combination of methyldopa and hydrochlorothiazide (Aldoril) produced immune hemolytic anemia
Vila JM, Blum L, Dosik H. Thiazide-Induced Immune Hemolytic Anemia. JAMA. 1976;236(15):1723-1724. doi:10.1001/jama.1976.03270160045029