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.
Does chlorthalidone differ from hydrochlorothiazide in pharmacokinetic and blood pressure-lowering effects?
Chlorthalidone is significantly more potent and longer-acting than hydrochlorothiazide, challenging the common assumption that they are interchangeable.
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.