Influences on GPs' decision to prescribe new drugs-the importance of who says what.

OBJECTIVES The aim of this study was to understand the range of factors that influence GPs' uptake of new drugs METHODS A total of 107 GPs selected purposively from high, medium and low new drug prescribing practices in two health authorities in the north west of England were interviewed using the critical incident technique with semi-structured interviews. Interview topics included reasons for prescribing new drugs launched between January 1998 and May 1999; reasons for prescribing the new drug rather than alternatives; and sources of information used for each prescribed drug. RESULTS Important biomedical influences were the failure of current therapy and adverse effect profile. More influential than these, however, was the pharmaceutical representative. Hospital consultants and observation of hospital prescribing was cited next most frequently. Patient request for a drug, and patient convenience and acceptability were also likely to influence new drug uptake. Written information was of limited importance except for local guidelines. GPs were largely reactive and opportunistic recipients of new drug information, rarely reporting an active information search. The decision to initiate a new drug is heavily influenced by 'who says what', in particular the pharmaceutical industry, hospital consultants and patients. The decision to 'adopt' a new drug is clinched by subsequent personal clinical experience. CONCLUSIONS Prescribing of new drugs is not simply related to biomedical evaluation and critical appraisal but, more importantly, to the mode of exposure to pharmacological information and social influences on decision making. Viewed within this broad context, prescribing variation becomes more understandable. Findings have implications for the implementation of evidence-based medicine, which requires a multifaceted approach.