Possible interaction between heparin and a sulphonylurea a cause of prolonged hypoglycaemia?

Reports to the Committee on Safety of Medicines show that skin reactions are the commonest adverse reaction to trimethoprim; the committee has had a few reports of cholestatic jaundice due to trimethoprim and to trimethoprim-sulphamethoxazole. Manufacturers of trimethoprim (Duphar) have received four reports of hepatic reactions: hepatitis (two), jaundice (one), and cholestatic jaundice (one). In previous reports similar hepatic reactions to combination antibiotics have been attributed to the sulphonamide component. I suspect that some of these reactions were due to trimethoprim. The mechanism for such cholestasis is obscure as trimethoprim interferes primarily with the metabolism of folic acid. As the reaction occurred late in life in this patient and was clearly related to exposure to the drug it is unlikely to have been any other form of benign cholestasis.