Haemolytic anaemia due to metformin

The haemolytic reactionin vivo is dependent on the presence of the drug and ceases shortly after the drug is discontinued. Since the antibody is usually IgG, spherocytosis and splenic destruction may occur. Penicillin and its congeners may lead to this type of reaction if the drug is given in very high doses. 3 Drugs causing immunohaemolytic anaemia aminosalicylic acid penicillins cephalosporins phenacetin chlorpromazine procainamide dapsone quinidine insulin rifampin isoniazid sulfonamides levodopa methyldopa melphalan mefenamic acid A literature search revealed only one other report of a similar side-effect due to metformin. 4 There have been no other reports to drug regulatory agencies or to the World Health Organisation Adverse Drug Reaction Monitoring Centre.