Chlorthalidone is approximately 1.5 to 2.0 times as potent as hydrochlorothiazide and has a much longer duration of action, though whether this causes differences in clinical outcomes is unknown.
Thiazide diuretics are one of the preferred pharmacologic treatments for hypertension. Hydrochlorothiazide and chlorthalidone have been the 2 most commonly used diuretics in major clinical trials. Treatment guidelines and compendia often consider these 2 drugs interchangeable agents within the class of thiazide or thiazide-like diuretics. Many sources list them as equipotent. Despite these beliefs, there is some suggestion that cardiovascular outcomes are not necessarily the same with these 2 drugs. We conducted a literature search from 1960 to 2003 to identify studies that evaluated the pharmacokinetic and blood pressure-lowering effects of these 2 agents. There are significant pharmacokinetic and pharmacodynamic differences between these diuretics. Chlorthalidone is approximately 1.5 to 2.0 times as potent as hydrochlorothiazide, and the former has a much longer duration of action. Whether these pharmacokinetic and pharmacodynamic features cause differences in outcomes is not known.
Carter et al. (Tue,) conducted a review in Hypertension. Chlorthalidone vs. Hydrochlorothiazide was evaluated on Pharmacokinetic and blood pressure-lowering effects. Chlorthalidone is approximately 1.5 to 2.0 times as potent as hydrochlorothiazide and has a much longer duration of action, though whether this causes differences in clinical outcomes is unknown.