Chlorthalidone users more responsive, but less adherent than HCTZ users
A retrospective cohort study investigated medication tolerance in veterans who had recently started either HCTZ (120,000 patients) or chlorthalidone (2200 patients) and were followed for a year.4 Most received doses between 12.5 and 25 mg of active drug.
One primary outcome was “nonpersistence,” defined as failure to refill the medication after double the number of days as the initial prescription. The other was “insufficient response,” defined as the need to start another antihypertensive medication. Chlorthalidone users were less likely than HCTZ users to have an insufficient response (odds ratio [OR]=0.71; 95% CI, 0.63-0.80) but more likely to exhibit nonpersistence (OR=1.6; 95% CI, 1.5-1.8).
RECOMMENDATIONS
For primary hypertension, the United Kingdom’s National Institute for Health and Care Excellence (NICE) recommends diuretic monotherapy in patients older than 55 years who are poor candidates for calcium channel blockers.5 If a diuretic is to be initiated or changed, NICE recommends chlorthalidone (12.5-25 mg daily) or indapamide (1.5-2.5 mg daily) in preference to HCTZ. The guideline set forth in the eighth annual report of the United States Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure makes no distinction between chlorthalidone and HCTZ; it refers only to “thiazidetype diuretics.” Thiazide-type diuretics are listed as one option (along with angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and calcium channel blockers) for initial monotherapy in nonblack patients.6