Objective : To analyze serious adverse drug reactions (ADRs) in terms of their occurrence, the related factors and the necessary means to avoid such ADRs, and proposal of possible preventive measures against ADRs.
Design : Case series.
Methods : Out of 598 cases collected through an in-patient drug monitoring conducted from April 1990 to March 1996 in Hospital T, 59 cases which were of Grade 3 of the Ministry of Health and Welfare Standards for Severity Classification of ADRs were selected for this study. By classifying the causes of and the possibilities to avoid reactions in 59 cases, we discussed measures to prevent serious reactions to drugs.
Results : Symptoms involved were, in descending order, hypersensitivity, hepatic disorder, blood disorder, renal failure, cadiovascular system disorder, and other symptoms. Causal drugs were, in descending order, antibiotics, central nervous system drugs, circulatory drugs, gastrointestinal drugs, and other drugs.
Regarding the causes for the ADRs, factors involved in “usage”, such as indication and dosage, represented the highest rate, 40.7%. In a detailed survey of the possible avoidance of such reactions, 49.2% of serious ADRs were judged preventable by careful administration of the drugs. Further, 15.3% of the cases were thought to have resulted from a lack of or an inadequate description in the package insert.
Conclusions : The study indicates that the following steps are necessary to prevent ADRs. : (1) To be appropriately cautious to indications and dosages of the drug (including, in particular, indications and dosages for the aged, and renal failure or allergic patients, and the adjustment of dosage on the basis of drug-drug interaction); (2) To adhere strictly to contraindication ; (3) To offer suitable information on the ADRs to the patient who has experienced such a reaction ; and, (4) To be aware of unusual conditions by careful follow-up at an early stage after the administration.
The following action plans were considered important for carrying out the steps mentioned above : 1) to deepen medical workers awareness to prevent ADRs ; 2) to establish a system that can correctly offer fundamental and essential information to physicians ; 3) to standardize drug treatment according to patient condition (age, renal-failure, etc.) and to establish a safety assurance system.