[Pharmacologic surveillance and safety evaluation of new drugs].Acta Med Port. 1991 May-Jun; 4(3):141-6.AM
Efficacy and safety evaluation are the main objectives of clinical trials. Through a rigorous scientific methodology they compare the efficacy of the new drugs with that of standard drugs or placebo. However the design of clinical trials in phase III is more centered in the study of efficacy than in its safety. Other reason, apart this, is a natural consequence of the low number of patients recruited for this phase when the incidence of most type B adverse drug reactions is usually of the order of 1:10(-4). Therefore it is the author's contention that post-marketing (phase IV) trials and surveillance should become commoner practices since they can contribute for a permanent evaluation of drugs safety after their approval and introduction in the market.