Change in the established prescribing habits of general practitioners: an analysis of initial prescriptions in general practice.

The aim of this study was to describe the types of drugs prescribed by general practitioners in a sample of initial (rather than repeat) prescriptions, the additions and deletions made to a doctor's repertory and the factors influencing these changes. The method used here enabled repeat prescriptions to be excluded as these are an inaccurate reflection of the current habits of the prescriber. A total of 201 (74%) of the principal general practitioners in the Grampian region participated. Data were obtained by substituting special prescription pads containing duplicate forms which allowed additional data to be recorded at the time of prescribing, including perceived influences that had resulted in changes from established choices of drug therapy. A sample of 100 forms were collected on seven occasions from each doctor over a one year sample period. Prescribers on average selected a preparation that they had only started to use within the last 12 months (that is newly adopted to their repertory) in 5.4% of initial prescriptions. These changes mostly involved antibiotics and analgesics and were occasioned mainly by the influence of the 'limited list' regulations, pharmaceutical company representatives and hospital specialists. We conclude that general practitioners were not unduly influenced by commercial sources of information, and that their prescribing habits were stable and conservative. The paper presents a case for the separate analysis of initial and repeat prescriptions as an essential step in producing more informative data on prescribing.