Levodopa hemolytic anemia with

Very occasionally there are falls in white blood cell connt, hemoglobin, and hematocrit. The Coombs test can be positive and there is an isolated report of hemoljdic anemia and another of thrombocytopenia with a positive antinuclear antibody test (SED-12, 315). An otherwise unexplainable acnte severe non-hemolytic anemia in an elderly man taking levodopa with benserazide has also been observed (SEDA-12,124). 

Levodopa should not be used in patients with a history of mental illness, hemolytic anemia, or any serious organic disease. 

Overall, however, the reason that only some patients develop autoantibodies, and that only some of those have hemolytic disease, is not known. In an effort to explain why patients may have a positive result from a Coombs test and no hemolysis, Kelton demonstrated that methyldopa impairs the abihty of these patients to remove antibody-sensitized cells. In Coombs-positive patients receiving methyldopa, patients with impairment of the reticuloendothelial system could not clear the RBCs coated with autoantibodies from their bloodstream, and therefore hemolysis did not occur. Patients with hemolysis had no impairment of the reticuloendothelial system. Procainamide has also been reported to cause a positive result on the direct anti-human globulin test and hemolytic anemia. Other drugs that have been reported to cause autoimmune hemolytic anemia include levodopa, mefenamic acid, and diclofenac. ... 

Some other drugs produce an autoimmune hemolytic anemia in which the antibodies are directed towards native antigens on the red cell surface, while the drug does not seem to function as a hapten in the reaction. This type of autoimmune hemolytic anemia has been described following treatment with levodopa, methyl-dopa, and mefenamic acid (Worrledge et al. 1966 Worrledge 1973). With a-methyldopa, clinically significant hemolysis develops in less than 1 % of individuals... 

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