Introduction/Objective: Clinical guidelines need to take account of their economic implications. The aim of the work was to develop valid efficiency based guidelines for the general practice use of four drug groups: ACE inhibitors in heart failure; "antidepressants; aspirin as an antithrombotic; and NSAIDs in osteoarthritis.

Methods: The guidelines were developed by 2 parallel group processes involving literature review; and multidisciplinary development group process. Explicit literature searches were performed and study effects summarised using meta-analysis. Information on harm and cost were identified.

Results: The process took 12 months; the groups met monthly on up to 8 occasions. Recommendations were made in the light of clinical effectiveness, side effects, harm and cost. This method allowed explicit calculation of the extra costs of using a drug, the potential cost consequences of particular drug choices, and the benefit of certain drug choices in terms of side effects or harm. Group members required education in both meta-analysis and health economics; they were able to make recommendations based on the data available.

Discussion: There is increasing interest in the development of evidence-based guidelines. Within the focused area of drug use it has been possible to extend this process to produce efficiency-based guidelines. This is a complex and expensive process. The method requires testing across a number of broad disease categories.