Adverse drug reactions-a matter of opinion.

The accurate identification of adverse drug reactions (ADRs) is difficult because ADRs usually present no unique clinical or laboratory findings that demarcate them from the manifestations of concurrent illnesses. The identification of ADRs depends on the clinical assessments of physicians-sometimes the clinician treating the patient and at other times a clinical pharmacologist. Considering the complex and subjective nature of clinically identifying ADRs, how accurately are ADRs identified? To answer this question, three clinical pharmacologists each independently evaluated 60 selected cases to determine if medication, alcohol, or "recreational" drugs had caused the hospitalization. The three clinical pharmacologists agreed on only 30 cases (50%), and 27 of these were thought to be unrelated to medications. In 19 of the 30 cases about which the clinical pharmacologists disagreed, they disagreed on whether or not a medication-or alcohol-related event had occurred at all. The clinical pharmacologists disagreed with the physicians treating the patient in 22% to 37% of the cases, but because of the differences among the pharmacologists, the treating physicians agreed with at least one of them in 95% of the cases. Complete agreement between the clinical pharmacologists and the treating physicians occurred in 47% of the cases. This degree of disparity in the clinical identification of ADRs shows that the evaluation of ADRs is subjective and imprecise. The accurate identification of ADRs awaits the development of an objective technique for recognizing ADRs.