Abstract
Pharmaceutical manufacturers are obliged to report results of clinical application of a new drug for six years after its approval.These clinical results, together with the data obtained before the approval, are comprehensively carried in “Reporting of Adverse Drug Reactions” issued from the Ministry of Health and Welfare. Post marketing surveillance (PMS) data have a significant value because they provide information on adverse reactions in cases which cannot be obtained during development of the drug.We attempted to analyze the data primarily on the basis of the incidence of adverse reactions, in order to use the data as an important information source on drugs.
We put the data from No.27 (October, 1977) to No.109 (July, 1991) into a computer and examined them. When the incidence of adverse reactions was compared before approval (A) and after approval (B), the incidence B was lower in 91.3%(316 of 346) of the cases.All the remaining 8.7%(30 of 346) of the cases had some special reasons. One of the reasons for decrease in the incidence B is increase in the number of patients observed.In PMS, pharmaceutical manufacturers are required to report approximately 10 times as many patients as during the development of drugs. Another reason is that some cases of adverse reactions may not be reported depending on individual physicians' judgement.Moreover, some physicians may not be aware of the adverse reactions.
From our analysis of the results, it is impossible to regard A and B as equivalent.In Japan, incidence of adverse reactions listed in package inserts is expressed as a total average of A and B. Because of the above-mentioned reasons, however, we think that A and B should be indicated separately.
