Comparative Effectiveness of Chlorthalidone Versus Hydrochlorothiazide and Dose-Response of Amiloride on Blood Pressure and Biochemical Parameters.
Leonardo G Bottino, Sandra C Fuchs, Beatriz P Camilo et al.
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In 30 seconds
This 12-week factorial randomized clinical trial compared chlorthalidone 25 mg with hydrochlorothiazide 50 mg, and amiloride 5 mg with 10 mg, assessing office and ambulatory blood pressure and laboratory parameters. Chlorthalidone and hydrochlorothiazide produced similar blood pressure effects at the tested 1:2 dose ratio; the between-group difference in systolic 24-hour pressure (hydrochlorothiazide minus chlorthalidone) was -1.1 (95% CI, -8.0 to 5.9; P =0.8). Amiloride doses also had similar blood pressure effects, with no clear dose-response relationship. Laboratory measures were generally similar, although serum sodium decreased more with 10 mg amiloride.
Key findings
- Systolic 24-hour BP difference for hydrochlorothiazide versus chlorthalidone was -1.1 (95% CI, -8.0 to 5.9; P =0.8).
- Chlorthalidone 25 mg and hydrochlorothiazide 50 mg had similar office and ambulatory BP effects and laboratory parameters.
- Amiloride 5 mg and 10 mg had similar BP effects; serum sodium decreased more with 10 mg, while other laboratory parameters were similar.
Why it matters
The findings inform comparisons between commonly used diuretic regimens at the doses studied. They suggest that doubling the hydrochlorothiazide dose relative to chlorthalidone yielded similar BP effects over 12 weeks, while increasing amiloride from 5 mg to 10 mg did not produce a clear additional BP effect. The sodium difference is relevant when considering biochemical monitoring.
What to keep in mind
Follow-up was limited to 12 weeks, so the trial does not establish longer-term comparative effects.