Authors: Rebecca Vigen Rick A Weideman Robert F Reilly
Publish Date: 2010/08/25
Volume: 43, Issue: 3, Pages: 813-819
Abstract
In the 1980s a change occurred in hydrochlorothiazide prescribing practices for hypertension from highdose 50 mg/day to lowdose 125–25 mg/day therapy However randomized controlled trials RCT for prevention of calciumcontaining kidney stones CCKS employed only high doses ≥50 mg/day We hypothesized that these practices have resulted in underdosing of hydrochlorothiazide for prevention of CCKS Patients with a filled prescription for thiazide diuretics that underwent a 24h urine stone risk factor analysis were eligible Those with evidence that thiazide was prescribed for CCKS were further analyzed Of 107 patients 102 were treated with hydrochlorothiazide 4 with indapamide and one with chlorthalidone Only 35 of hydrochlorothiazidetreated patients received 50 mg/day a dose previously shown to reduce stone recurrence Fiftytwo percent were prescribed 25 mg and 13 125 mg daily doses that were not studied in RCT Evidencebased hydrochlorothiazide use was suboptimal regardless of where the patient received care Nephrology or Endocrinology clinic In a small subset of patients n = 6 with 24h urinary calcium excretion measured at baseline and after 2 hydrochlorothiazide doses 25 and ≥50 mg there was a trend toward decreased urinary calcium excretion as the dose was increased from 25 to ≥50 mg/day p = 0051 Lowdose hydrochlorothiazide was often used for prevention of CCKS despite the fact that there is no evidence that it is effective in this setting This may have resulted from a practice pattern of using lower doses for hypertension therapy or a lack of knowledge of RCT results in treatment of CCKS
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