The influence of national guidelines on antihypertensive prescribing patterns.

Efforts to influence medical practice include the formation of expert medical panels who make recommendations for the evaluation and treatment of clinical problems. Despite the considerable expense and effort that go into these activities, it is unclear whether they are successful. Recent studies have evaluated whether recommendations from the Fifth Joint National Committee on the Detection, Evaluation, and Treatment of High Blood Pressure (JNC V) published in 1993 influenced antihypertensive prescribing patterns. These included a national study of medications dispensed by retail pharmacies and an evaluation of antihypertensive prescribing patterns in US Veterans Affairs (VA) medical facilities. Despite recommendations from JNC V that hydrochlorothiazide and beta-blockers be used as first choice for most hypertensive patients, calcium antagonists and angiotensin converting enzyme (ACE) inhibitors were the most common drugs prescribed for hypertension in both 1992 (before JNC V) and 1995 (after JNC V). In retail pharmacies, changes in antihypertensive drug dispensing patterns from 1992 to 1995 reflected increased use of calcium antagonists and ACE inhibitors and decreased use of diuretics and beta-blockers, suggesting that JNC V recommendations had little effect on prescribing patterns. Similar patterns of antihypertensive drug use were found in VA facilities. The reasons for the lack of influence of JNC V recommendations on antihypertensive prescribing patterns must be explored and alternative ways of educating health care providers implemented.