title: Minimum effective dosage in the drug treatment of hypertension: a cost effective strategy for prescribers.
abstract: The cost effectiveness of antihypertensive therapy is increasingly called into question. Minimising the prescribed dose of antihypertensive medications is one potentially effective method of improving cost effectiveness. The minimum effective dose of an antihypertensive medication is defined as that dose above which any further increase is unlikely to result in significant additional lowering of blood pressure. A review of the available clinical trials was undertaken to determine the minimum effective dosages for commonly prescribed beta blockers. These minimum effective dosages were then compared with the average dosages currently prescribed in New Zealand general practices, as determined by a random national survey of prescriptions. The comparison indicated that several beta blockers--including atenolol, metoprolol, propranolol and oxprenolol--are probably being prescribed at excessively high doses. These findings were supported by the results of a general practice based prospective study of beta blocker dose reduction. Seventy-three hypertensive patients on a range of beta blockers were monitored for three months, following a halving of their medication dosage. The results of this study indicated that despite 50% reduction in dosage, there was no loss of antihypertensive effect in this patient population, although heart rate increased. Together, these two studies demonstrate the clinical relevance of the concept of a minimum dosage for beta blockers. A strategy is outlined for reducing the doses for several beta blockers in a significant proportion of hypertensive patients with major cost savings.
authors.affiliation: Department of Medicine, Wellington School of Medicine.
authors.forename: T J
authors.initials: TJ
authors.lastname: Maling
authors.forename: I
authors.initials: I
authors.lastname: Kawachi
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage*; D003362:Cost-Benefit Analysis; D004305:Dose-Response Relationship, Drug; D011307:Drug Prescriptions / Q000191:economics; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000191:economics; D008297:Male; D008875:Middle Aged; D009520:New Zealand
chemical_list: D000319:Adrenergic beta-Antagonists