A Study of Prescribing Patterns

Abstract

The Los Angeles County-University of Southern California Medical Center is one of the largest in the world. Over 600,000 outpatient prescriptions are processed yearly. These prescriptions are being processed, as a part of the drug dispensing system, by means of computer terminals. As a first step in controlling irrational prescribing, three types of undesirable or inappropriate prescriptions were defined and identified by physicians and pharmacists at the Medical Center. These are: 1. excessive drug quantities specified in individual prescriptions, 2. undesirably frequent prescriptions for the same drug, and 3. inappropriate concurrent prescriptions for different drugs. Of 52,733 consecutive prescriptions for the 78 drug products most frequently dispensed to outpatients, representing more than four fifths of all outpatient prescriptions, 13% represented excessive-quantity prescriptions. Most frequently involved were sedatives and tranquilizers. As many as 1,300 tablets of one such agent was dispensed on a single prescription. Only 1.7% of all prescriptions were judged to involve too frequent prescribing of a drug. However, analyses of patient drug records showed that some outpatients were receiving as many as 54 prescriptions over a 112-day period. Numerous examples were found of concurrent prescriptions of two different drug products which could result in serious drug interaction or potentiation.