Stimulating reporting of adverse drug reactions by using a fee.

which may lead to serious postoperative bleeding are more commonly associated with certain cephalosporins having the N-methylthiotetrazole side chain-' but have been noted with others -such as cefuroxime -lacking this side chain.23 Some investigators have suggested that the pharma- cokinetic profile of an antibiotic is important if it is to be given only preoperatively and have advocated the use of antibiotics with prolonged elimination half lives-for example, ceftriaxone," which is not available in Britain. Our results imply that this is not necessary for operations lasting up to 90 minutes. The half lives of both cephalosporins used here are in the order of one to one and a half hours. Cefotaxime, however, undergoes desacetylation to a metabolite, desacetylcefotaxime, which has broad spectrum antibiotic activity and hence prolongs the duration of antibiotic activity of the parent drug.24 Nevertheless, for operations which extend beyond 90 minutes our results suggest that a peroperative "topping up" dose may be beneficial (though only 107 of 907 (11 8%) operations in this study were of greater than two hours' duration). It is evident that prophylactic postoperative doses of cefuroxime plus metronidazole confer no additional benefit over a single preoperative dose of cefotaxime plus metronidazole.