Low Dose Nicotinamide as an Adjunctive Therapy to Calcium Carbonate for Control of Hyperphosphatemia in Hemodialysis Patients

Background: Hyperphosphatemia remains a common problem in patients on maintenance dialysis and contributes to the development of secondary hyperparathyroidism. Current therapies for the treatment of hyperphosphatemia are frequently insufficient to achieve the recommended K/DOQI goal of maintaining serum phosphorus level between 3.5 and 5.5 mg/dl. Niacinamide inhibits intestinal sodium/ phosphorus co transporters and reduces serum phosphorus level in some clinical studies. So, we aimed to evaluate the safety and the efficacy of nicotinamide as adjunctive therapy to calcium carbonate (as calcium based phosphate binder) in hemodialysis patients. Methods: Sixty hemodialysis patients with serum phosphorus level ≥ 5.0 mg/dl were randomly assigned to 8 weeks of the study. Patients were divided into two groups: (group I) (control group): 30 cases calcium carbonate only and (group II) (study group): 30 cases received a combination of calcium carbonate and nicotinamide. Nicotinamide dose was started as 500mg/day and increased on 8 th day to 1000 mg/day. Results: In the study group (nicotinamide group): serum phosphorus level fell significantly (p<0.001), calcium × phosphorus product dropped significantly (p<0.001), with a significant elevation of serum calcium (p<0.05). In the control group: there was insignificant change in former parameters (p values>0.05). Intact parathyroid hormone, uric acid, platelet count, total cholesterol, hemoglobin, ASAT, and ALAT and lipid profile remained insignificantly changed in both groups. Diarrhea, flushing and skin rash were the major adverse effects seen with nicotinamide therapy resulting in early withdrawal of 4 patients from the study. Conclusion: In hemodialysis patients, nicotinamide in single dose of 1000 mg daily can effectively reduce serum phosphorus level when administered with calcium carbonate (as phosphate binder) with less potential side effects reported.