Adverse reactions to antibiotic drugs: the present scope of the problem in outpatient care and possibilities for improvement.

This study provides estimates of the frequency of adverse reactions due to antibiotic therapy and the effectiveness of two approaches in reducing them. Calculations were made of the extent of decrease in adverse reactions if physicians prescribed the drug of choice, and if antibiotics were prescribed only when necessary. The risks of adverse reactions and the estimates of unnecessary prescribing were obtained from the published medical literature. The number of prescriptions and the diseases treated were obtained from a commercial data source (IMS America). It was estimated that on average one antibiotic prescription per inhabitant was prescribed in outpatient care, that 7.6 percent of the population had adverse reaction due to antibiotic therapy, and that 1.4 percent had a serious reaction in 1974 in the United States. If physicians had prescribed the drug of choice, the number of adverse reactions would have been reduced by 37 percent. If antibiotics had been prescribed only when necessary, but the pattern of prescribing different antibiotics had been the same, one third of the adverse reactions would have occurred. If physicians had prescribed the drug of choice and only when necessary, about one fifth of the adverse reactions would have occurred. The actual number of avoidable adverse reactions may be larger or smaller than these estimates, but the magnitude of the effect indicates an area for concern.