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December 14, 1970

Drug Interactions With Anticoagulants

Author Affiliations

From the departments of medicine and pharmacology, University of Cincinnati College of Medicine, Cincinnati.

JAMA. 1970;214(11):2035-2038. doi:10.1001/jama.1970.03180110045010

Combined or multiple drug therapy has become an accepted fact in medical practice. A study of hospitalized patients at the Johns Hopkins Hospital revealed that these patients received an average of 13 different drugs during their hospital stay.1 The Division of Clinical Pharmacology at the University of Cincinnati surveyed prescriptions for 821 outpatients of the Cincinnati General Hospital medical clinics. Although 15% of these patients were not treated with drugs, a few patients received as many as eight drugs at one time. The average was two drugs per patient. In a study from Florida, ambulant patients admitted taking an average of 3.5 different drugs (including over-the-counter drugs) during the two months prior to their outpatient clinic visit. Only 9% of these patients denied taking any drugs.2 The incidence of adverse drug reactions has been shown to increase as the number of drugs taken concurrently increases.3 Therefore, it