-As presented in an earlier newsletter
, low dose therapy has considerable anti-hypertensive effect.
-Chlorthalidone is both more potent and longer acting than HCTZ. While the dose of HCTZ can be increased to match the potency of chlorthalidone, HCTZ must be given twice/day to ensure 24hr anti-hypertensive efficacy.
-Since the duration of action of HCTZ is well under 24hrs, its anti-hypertensive effect wanes in the early morning hours, the time at which BP is highest and the most cardiovascular events occur
-Study limitations include the small number of patients randomized (versus screened) and the large standard deviation around a given BP reduction. The exclusion criteria are also clinically relevant. Finally, the study was underpowered to detect adverse events.
-Despite the above limitations, the results are consistent with the existing literature and generalizable to most hypertensives (apart those with a GFR < 30cc/min). As such, i
n my own practice, I rarely use HCTZ but instead favor chlorthalidone (12.5, 25mg) or indapamide (1.25, 2.5mg) as my thiazide of choice.