Efficacy and tolerance of three different calcium acetate formulations in hemodialysis patients

Background: Calcium acetate (CaAc) is an effective phosphate binder in pati ents with chronic renal failure. However, an important side effect is gastr o-intestinal discomfort. Phos-ex(R) (Cablon, The Netherlands) is the only c ommercially available non-coated CaAc formulation in our country. We develo ped two new CaAc formulations: neutral-coated CaAc (NCCaAc) and enteric-coa ted CaAc (ECCaAc). Methods: In a randomised double-blinded cross-over trial we compared effica cy and tolerance of thr three formulations in 19 stable hemodialysis patien ts, with a mean age of 63 years (range, 36-85), who had been on hemodialysi s for 19 months (range, 6-47). Patients were randomised to receive NCCaAc o r ECCaAc, with meals, for a period of 10 weeks and after cross-over for ano ther 10 weeks. During a third non-blinded period, patients received Phos-ex (R) for 10 weeks. Results: Serum phosphate was significantly higher with ECCaAc compared to N CCaAc (1.89+/-0.07 vs. 1.70+/-0.08 mmol/l, P < 0.05). Serum Ca was signific antly lower with ECCaAc compared to NCCaAc or Phos-ex(R) (2.38+/-0.04, 2.47 +/-0.04 and 2.48+/-0.04 mmol/l, P < 0.05). There were less hypercalcemic an d more hyperphosphatemic events in the ECCaAc period, compared to the other periods, The daily CaAc dose and dietary intake of calcium, phosphate, pro tein and calories were comparable in all three periods. With Phos-ex(R), pa tients noticed more gastro-intestinal complaints than with to NCCaAc and EC CaAc. Two patients stopped taking Phos-ex(R) because of side effects. Conclusions: In hemodialysis patients, phosphate control and tolerance were both influenced by the formulation of CaAc. Although phosphate control was adequate with all three formulations of CaAc, ECCaAc was less effective co mpared to NCCaAc or Phos-ex(R). NCCaAc and ECCaAc were better tolerated tha n Phos-ex(R). Regarding efficacy and tolerance, NCCaAc was the best calcium acetate formulation. (C) 1999 Elsevier Science B.V. All rights reserved.