Discrepant Antihypertensive Dose Recommendations

Abstract

In 1997 and 2003 the Joint National Committee on Prevention, Detection, Evaluation and Treatment of Hypertension (JNC VI and JNC VII) gave beginning dose recommendations for antihypertensive drugs that were lower than those found in drug package inserts and the Physicians’ Desk Reference (PDR). Popular handheld Personal Digital Assistant (PDA) programs recommended the JNC starting dose only 35% of the time and standard textbooks 34% of the time. Prescribing patterns at an academic medical center reflected PDR guidelines for the thiazide diuretics and a calcium channel blocker, but they were closer to JNC guidelines for beta adrenergic blockers. The higher thiazide doses recommended by the PDR were associated with hypokalemia. The PDR gives 2.4 mg of clonidine daily as the maximum effective dose, twice the maximum dose recommended by the JNC. High clonidine doses were used 14% of the time in inpatients and in 9% of outpatient prescriptions at an academic medical center, even though high doses of clonidine raise rather than lower blood pressure. When recommendations for high doses of antihypertensive medications in the package insert conflict with JNC recommendations, the package insert recommendations carry through to the PDR, textbooks, PDAs, and to some physician prescriptions.