Amoxicillin-induced immune hemolysis.

Severe hemolysis occurred in a 51-year-old female after a 17-day course of intravenous amoxicillin. A strongly positive direct antiglobulin test (anti-IgG titer 1:2,000) ensued which disappeared after withdrawal of the drug. Both the patient's serum and eluate obtained from the patient's red cells contained an IgG antibody which reacted with red blood cells coated in vitro with amoxicillin, but not with uncoated cells. In addition, high-titer antipenicillin, antiampicillin and antiamoxicillin IgG antibodies could be demonstrated in her serum by a RAST-based solid-phase radioimmunoassay. The patient's hemolysis gradually subsided within 1 week after discontinuing the drug. This is the first report of amoxicillin-induced immune hemolytic anemia.