title: Comparing clinical effectiveness and drug toxicity with hydrochlorothiazide and chlorthalidone using two potency ratios in a managed care population.
abstract: This study compared the clinical effectiveness and drug toxicity of chlorthalidone and hydrochlorothiazide. Electronic health records and claims data were used to identify patients initially prescribed chlorthalidone or hydrochlorothiazide. A total of 214 patients prescribed chlorthalidone 25 mg were matched with 428 patients prescribed hydrochlorothiazide 25 mg (1:1 potency ratio) and 214 patients prescribed hydrochlorothiazide 50 mg (1:2 potency ratio). Mean systolic blood pressure/diastolic blood pressure values at least 30 days after initial prescription were lower with chlorthalidone (132.2/74 mm Hg) compared with hydrochlorothiazide 25 mg (137.0/77.5 mm Hg) and hydrochlorothiazide 50 mg (138.6/78.5 mm Hg) (P<.05 for all comparisons). Goal systolic blood pressure/diastolic blood pressure values were achieved in a higher percentage of patients prescribed chlorthalidone (45.0%/78.3%) than with either hydrochlorothiazide 25 mg (32.1%/63.9%) or hydrochlorothiazide 50 mg (32.8%/68.9%) (P<.05 for all comparisons). Mean serum potassium was 3.94 mEq/L with chlorthalidone 25 mg, 4.13 mEq/L with hydrochlorothiazide 25 mg (P<.01 vs chlorthalidone), and 3.96 mEq/L with hydrochlorothiazide 50 mg. These findings indicate that chlorthalidone 25 mg is associated with a better antihypertensive response than hydrochlorothiazide 25 mg or 50 mg, without clinically significant differences in serum potassium.
authors.affiliation: Department of Clinical Pharmacy, Skaggs School of Pharmacy & Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO; Department of Family Medicine, School of Medicine, University of Colorado, Aurora, CO.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Saseen
authors.forename: Vahram
authors.initials: V
authors.lastname: Ghushchyan
authors.forename: Kavita V
authors.initials: KV
authors.lastname: Nair
mesh_terms: D000959:Antihypertensive Agents / Q000009:adverse effects / Q000494:pharmacology / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002752:Chlorthalidone / Q000009:adverse effects* / Q000494:pharmacology / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D057286:Electronic Health Records; D005260:Female; D006801:Humans; D006852:Hydrochlorothiazide / Q000009:adverse effects* / Q000494:pharmacology / Q000627:therapeutic use*; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008329:Managed Care Programs; D008875:Middle Aged; D012189:Retrospective Studies; D013599:Systole / Q000187:drug effects / Q000502:physiology; D016896:Treatment Outcome; D014481:United States
chemical_list: D000959:Antihypertensive Agents; D006852:Hydrochlorothiazide; D002752:Chlorthalidone