Comparative Antihypertensive Effects of Hydrochlorothiazide and Chlorthalidone on Ambulatory and Office Blood Pressure.
From: Division of Clinical and Administrative Pharmacy, College of Pharmacy, University of Iowa, Iowa City, Iowa, USA. michael-ernst@uiowa.edu
Hypertension
- Publish Date: Mar 2006
- ISSN: 1524-4563
- Volume: 47
- Issue: 3
- Pages: 352-8
- Medium: Internet
- Language: English
- Citation (JAMA): Ernst Michael E, Carter Barry L, Goerdt Chris J, et al. Comparative Antihypertensive Effects of Hydrochlorothiazide and Chlorthalidone on Ambulatory and Office Blood Pressure.. Hypertension Mar 2006;47:352-8
Abstract
Low-dose thiazide-type diuretics are recommended as initial therapy for most hypertensive patients. Chlorthalidone has significantly reduced stroke and cardiovascular end points in several landmark trials; however, hydrochlorothiazide remains favored in practice. Most clinicians assume that the drugs are interchangeable, but their antihypertensive effects at lower doses have not been directly compared. We conducted a randomized, single-blinded, 8-week active treatment, crossover study comparing chlorthalidone 12.5 mg/day (force-titrated to 25 mg/day) and hydrochlorothiazide 25 mg/day (force-titrated to 50 mg/day) in untreated hypertensive patients. The main outcome, 24-hour ambulatory blood pressure (BP) monitoring, was assessed at baseline and week 8, along with standard office BP readings every 2 weeks. Thirty patients completed the first active treatment period, whereas 24 patients completed both. An order-drug-time interaction was observed with chlorthalidone; therefore, data from only the first active treatment period was considered. Week 8 ambulatory BPs indicated a greater reduction from baseline in systolic BP with chlorthalidone 25 mg/day compared with hydrochlorothiazide 50 mg/day (24-hour mean = -12.4+/-1.8 mm Hg versus -7.4+/-1.7 mm Hg; P=0.054; nighttime mean = -13.5+/-1.9 mm Hg versus -6.4+/-1.8 mm Hg; P=0.009). Office systolic BP reduction was lower at week 2 for chlorthalidone 12.5 mg/day versus hydrochlorothiazide 25 mg/day (-15.7+/-2.2 mm Hg versus -4.5+/-2.1 mm Hg; P=0.001); however, by week 8, reductions were statistically similar (-17.1+/-3.7 versus -10.8+/-3.5; P=0.84). Within recommended doses, chlorthalidone is more effective in lowering systolic BPs than hydrochlorothiazide, as evidenced by 24-hour ambulatory BPs. These differences were not apparent with office BP measurements.
Mesh Headings (Keywords): Adult, Blood Pressure, Blood Pressure Determination, Blood Pressure Monitoring, Ambulatory, Chlorthalidone, Cross-Over Studies, Drug Administration Schedule, Drug Interactions, Female, Humans, Hydrochlorothiazide, Hypertension, Male, Middle Aged, Office Visits, Single-Blind Method, Sodium Chloride Symporter Inhibitors, Time Factors
Check for Full Text / PubMed Unique Identifier (PMID): 16432050
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