Measuring the appropriateness of long-term prescribing in United Kingdom general practice - is the British National Formulary the 'Gold Standard'?

Background: The British National Formulary (BNF) is an independent professional publication which is highly respected and widely used by health care professionals in the U.K. In addition, it has been translated into several languages for use outside the U.K. A set of prescribing indicators has been developed to assess the appropriateness of long-term prescribing in U.K. general practice, using the BNF as the 'gold standard'. Objectives: The objective of this paper is to gain an understanding of why GPs may prescribe outside the recommendations given in the BNF. Methods: Twenty-two GPs were interviewed about a range of instances of potentially inappropriate prescribing for 101 patients under their care. These cases had been identified through the application of a set of prescribing indicators to the medical records of individual patients. The interview transcripts were repeatedly reviewed to identify cases where the GP felt that his/her prescribing was appropriate, even though it did not adhere to the guidance in the BNF. Results: The indicators which looked at total daily dose, recording of a valid indication, prescribing drugs of limited clinical value, generic prescribing and use of a potentially hazardous drug-drug combination all identified situations in which the GP would prescribe outside of the BNF guidance. In some cases they felt that the guidance was difficult to apply in clinical practice and in others they were either unaware of or did not believe it to be based on sound evidence. This may either be dictated by individual patient need or a consistent approach to prescribing a specific drug, based on their own clinical experience. Conclusions: This study has demonstrated that GPs will sometimes prescribe outside BNF guidance. With the continuing effort to improve prescribing in general practice, it is essential for those trying to influence prescribing behaviour to understand the complexity of this decisionmaking process. This should help inform the design and implementation of strategies to change behaviour in this area.