title: Additive hypocalciuric effects of amiloride and hydrochlorothiazide in patients treated with calcitriol.
abstract: To compare the effects of hydrochlorothiazide (HCTZ) alone and in combination with amiloride on urinary calcium excretion we performed 14 acute studies on 7 patients with vitamin-D-induced calciuria. Each patient was studied first with HCTZ alone, and 1-32 weeks later with the same or lower dose of HCTZ combined with amiloride. Administration of HCTZ alone did not change UCaV during the 1st day of therapy, and caused a significant reduction from 44.4 +/- 28.8 to 26.0 +/- 14.4 mg/m2/24 h (p less than 0.02) on the 4th day. In contrast, combined diuretic regimen caused a significant reduction in UCaV from 36.0 +/- 16.7 to 23.6 +/- 14.4 mg/m2/24 h (p less than 0.02) on the 1st day and further reduction to 13.3 +/- 6.9 mg/m2/24 h (p less than 0.01) on the 4th day. UCaV on the 4th day was significantly lower with the HCTZ-amiloride combination (p less than 0.05). The combined therapy caused a greater reduction in FECa/FENa than HCTZ alone on the 1st day (p less than 0.02) and on the 4th day (p less than 0.01). HCTZ-induced hyperkaluria, hypokalemia and alkalosis were prevented by the addition of amiloride. In another patient, low-dose HCTZ-amiloride had a maximal dissociative effect on FECa/FENa and was more effective than HCTZ given alone in a double dose. 3 patients were treated with the low-dose HCTZ-amiloride regimen for a total of 23 months. UCaV was kept persistently low.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000042:Absorption; D000293:Adolescent; D000328:Adult; D000584:Amiloride / Q000627:therapeutic use*; D002117:Calcitriol / Q000627:therapeutic use*; D002118:Calcium / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D004232:Diuretics; D004347:Drug Interactions; D004573:Electrolytes / Q000032:analysis; D005260:Female; D006801:Humans; D006852:Hydrochlorothiazide / Q000627:therapeutic use*; D007015:Hypophosphatemia, Familial / Q000150:complications / Q000188:drug therapy; D008297:Male; D011547:Pseudohypoparathyroidism / Q000188:drug therapy; D011719:Pyrazines / Q000627:therapeutic use*; D012279:Rickets / Q000150:complications / Q000188:drug therapy; D012964:Sodium / Q000378:metabolism
chemical_list: D004232:Diuretics; D004573:Electrolytes; D011719:Pyrazines; D006852:Hydrochlorothiazide; D000584:Amiloride; D012964:Sodium; D002117:Calcitriol; D002118:Calcium