Requirements for documentation of clinical effects of antibiotics

Documentation of clinical and microbiological efficacy and safety of antibiotics require well designed studies involving large number of patients. In principal, all studies should be comparative and the comparative agent(s) should be well documented in the literature. If possible, the studies should also be blind but if satisfactory blinding cannot be guaranteed, open studies will have to be performed, especially if injectible antibiotics are studied. The size of the trial, in terms of number of patients evaluable for clinical and especially for microbiological efficacy, must be sufficient either to prove significant differences between the regimens studied or to demonstrate equality with a reasonable type II error. Since the end-points used for efficacy and safety are not normally continuous, the patient materials must often be of a size which can only be achieved by multiple independent trials or multicentre trials. Thus, such studies are recommended.