News - Hypertension Week of Jan. 11, 2004/ Vol. 3 No. 02

Study: Unfavorable Trial Results Led to Decline in Alpha-Blocker Use for Hypertension

Recent results from a clinical trial on treating hypertension have changed the way physicians prescribe, and the way patients use, a certain high blood pressure drug, according to a study reported in the January 7 issue of the Journal of the American Medical Association.

In the spring of 2000, significant changes in the recommendations for alpha-blocker use occurred as a result of early, unfavorable results from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT).

That trial compared alpha-blockers, calcium channel blockers and ACE inhibitors to less expensive, generic diuretics for lowering blood pressure and preventing coronary heart disease and other cardiovascular events in high-risk hypertensive persons 55 years and older.

In January 2000, the arm of the study evaluating the alpha-blocker doxazosin was halted after researchers found that the risk of cardiovascular events with doxazosin was more than 25 percent greater than in patients treated with the thiazide diuretic chlorthalidone. The results were widely disseminated in news releases and journal publications.

After tracking trends in alpha-blocker prescriptions before and after the early termination of the doxazosin arm of the study, the researchers found steady increases in alpha-blocker prescriptions and use from 1996 through 1999.

However, a moderate reversal occurred once word got out about the early termination. Researchers found that new alpha-blocker prescription orders declined by 26 percent, dispensed alpha-blocker prescriptions by 22 percent and physician-reported alpha-blocker drug use by 54 percent between 1999 and 2002.

The researchers concluded that early termination results had a significant impact on alpha-blocker use and noted that declining pharmaceutical industry promotion may have contributed further to this decline.

However, the researchers also found that the lack of an abrupt and more pronounced decline in prescribing shortly after the ALLHAT results suggests slow and potentially incomplete diffusion of information from this clinical trial.

Other sources: JAMA. 2004; 291:54-62