Company:

Genzyme

Phosphate binder

Sevelamer carbonate 800mg; tabs.

Control of serum phosphorus in patients with chronic kidney disease on dialysis.

Patients with chronic kidney disease (CKD) can develop hyperphosphatemia as a result of retained phosphorus, which may lead to ectopic calcification. Hyperphosphatemia plays a role in the development of secondary hyperparathyroidism in CKD. In order to control serum phosphorus, the use of phosphate binders is used in addition to dietary phosphorus restriction and dialysis.

Sevelamer carbonate is a polymer that binds phosphorus in the dietary tract thereby decreasing the absorption of phosphorus. It also binds bile acids, which may interfere with normal fat absorption, including fat soluble vitamins. Additionally it has been shown to reduce the mean total and LDL cholesterol by 15–31%.

Renvela is a calcium-free, metal-free, nonabsorbed phosphate binder. It works similarly to Renagel (sevelamer HCl, also from Genzyme) with the benefit of a carbonate buffer.

The efficacy of sevelamer to control serum phosphorus in CKD patients on dialysis was determined from the effects of the hydrochloride salt to bind phosphate. Six clinical trials were conducted; one of the six used sevelamer carbonate. In this trial, Stage 5 chronic kidney disease patients on hemodialysis were entered into a five-week sevelamer HCl run-in period and 79 patients were randomized to receive either sevelamer carbonate 800mg tablets or sevelamer HCl 800mg tablets for eight weeks each, with no intervening washout. Study dose during the cross-over period was determined based on the sevelamer HCl dose during the run-in period on a gram per gram basis. The phosphate levels at the end of each of the two cross-over periods were similar. Average actual daily dose was 6g/day for both treatment groups. Thirty-nine of those completing the cross-over portion of the study were entered into a two-week washout period during which patients were instructed not to take any phosphate binders; this confirmed the activity of sevelamer in this study.

Take with meals. Patients not taking a phosphate binder: serum phosphorus >5.5 and <7.5mg/dL: 1 tablet 3 times daily; ≥7.5mg/dL: 2 tablets 3 times daily. May switch from sevelamer HCl on a gram/gram basis. Switching from calcium acetate: sevelamer carbonate 800mg approximates calcium acetate 667mg (see literature). Titrate by 1 tablet/meal at 2-week intervals to keep serum phosphorus between 3.5–5.5mg/dL; usual max 14g/day.

Not recommended.

Hypophosphatemia. Bowel obstruction.

Dysphagia. Swallowing disorders. Severe GI motility disorders. Major GI tract surgery. Monitor serum bicarbonate, chloride levels. Pregnancy (Cat.C). Labor & delivery.

May antagonize ciprofloxacin. Separate narrow therapeutic index drugs by 1 hour before or 3 hours after sevelamer, or consider monitoring (esp. with antiarrhythmics, antiepileptics). Adverse reactions: GI upset, constipation.

GI upset, constipation.

Tabs—30, 270

3/21/08