[Coagulation disorders caused by cephalosporins containing methylthiotetrazole side chains]

Treatment with MTT side chain containing cephalosporins can result in a clinically relevant coagulopathy due to a deficiency in active vitamin K dependent clotting factors. This complication is not caused by a decreased production of vitamin K by the intestinal flora, but by an interference with hepatic enzymes which synthetize active clotting factors. The gamma-carboxylation of glutamic acid components of inactive precursor peptides of vitamin K dependent clotting factors is inhibited as well as the reduction of vitamin K2,3 epoxide to active vitamin K. Predisposing factors for the coagulopathy caused by certain MTT side chain containing cephalosporins are a limited supply of vitamin K, impaired liver and renal function and a prolonged treatment.