Potential risks and prevention, Part 4: Reports of significant adverse drug events.

A summary analysis of three descriptive studies of significant adverse drug events (ADEs) was conducted. Case reports of ADEs published in Clin-Alert during 1976-97 were the source of information on ADEs, including drug-induced deaths, disabilities, and threats to life. The results of the three studies were compared, and recommendations were made. During the 21-year period, 1520 significant ADEs were reported (29% resulting in death, 15% in permanent disability, and 56% in life threats). Event types were distributed as adverse drug reactions (52%), allergic drug reactions (25%), medication errors (15%), and drug interactions (8%). Only 12% of the drug interactions were classified as having highest significance by one drug information reference, while 32% of the drug interactions were unclassified. Typically, patients were 40-69 years old and relatively healthy or only moderately ill and had received usual dosages. However, 29% of the patients with a drug-induced permanent disability were less than 10 years old. Only 17% of the drugs that could have been monitored by blood level tests were so monitored. The drug categories most commonly involved in ADEs were central-nervous-system agents, antimicrobials, antineoplastics, and cardiovascular agents. The nervous, hematopoietic, cardiovascular, and respiratory systems were affected the most. Faulty prescribing was the most common reason for medication error, and wrong dosage was the most common type of error. A lawsuit was reported in 13% of the cases. Overall, 52% of the cases were judged to have been preventable; of these, 50% could have been prevented by a pharmacist. Litigation was reported for 13% of the cases; settlements and judgments averaged $3.1 million. A summary analysis of more than 1500 published case reports of ADEs for 1976-97 yielded information on possible risk factors for drug-related deaths, disabilities, and life threats and on which events may have been preventable.