Phoscut

Description

The active ingredient in Phoscut is sevelamer carbonate, a polymeric amine that binds phosphate and is meant for oral administration. Sevelamer carbonate is an anion exchange resin, with the same polymeric structure as sevelamer hydrochloride, in which carbonate replaces chloride as the counter ion. While the counter ions differ for the two salts, the polymer itself, the active moiety involved in phosphate binding, is the same.

Sevelamer carbonate is known chemically as poly(allylamine-co-N,N’-diallyl-1,3 diamino-2-
hydroxypropane) carbonate salt. Sevelamer carbonate is hygroscopic, but insoluble in water.

Pharmacology

Patients with CKD retain phosphorus and can develop Hyperphosphatemia. When the product of serum calcium and phosphorus concentrations (Ca*P) surpasses 55 mg/dL, there is an increased risk that ectopic calcification will occur. Hyperphosphatemia plays a role in the development of secondary hyperparathyroidism in renal insufficiency.

Management of Hyperphosphatemia includes Diet, Dialysis and use of Phosphate Binders. Sevelamer carbonate taken with meals has been shown to control serum phosphorus concentrations in patients with CKD who are on dialysis.

Mechanism of Action

Phoscut contains sevelamer carbonate, a non-absorbed phosphate binding crosslinked polymer, free of metal and calcium. It contains multiple amines separated by one carbon from the polymer backbone. These amines exist in a protonated form in the intestine and interact with phosphate molecules through ionic and hydrogen bonding. By binding phosphate in the gastrointestinal tract and decreasing absorption, Sevelamer carbonate lowers the phosphate concentration in the serum (serum phosphorus).

Drug Interactions

It may develop drug interaction with the following drugs

1. Ciprofloxacin
2. Digoxin
3. Warfarin
4. Enalapril
5. Metoprolol
6. Iron

Overdosage

Sevelamer hydrochloride, which contains the same active moiety as sevelamer carbonate, has been given to normal healthy volunteers in doses of up to 14 grams per day for eight days with no adverse effects. In CKD patients on dialysis, the maximum dose studied was 14 grams of sevelamer carbonate and 13 grams of sevelamer hydrochloride. There are no reports of overdosage with sevelamer carbonate or sevelamer hydrochloride in patients. Since sevelamer is not absorbed, the risk of systemic toxicity is low.

Contraindications

Phoscut is contraindicated in patients with bowel obstructions.

Warnings & Precautions

Serious cases of dysphagia, bowel instruction, and perforation have been associated with Sevelamer use some requiring hospitalization and surgery.

Adverse reactions

Sevelamer carbonate may cause constipation ,if left untreated it may lead to severe complications. Patients should be cautioned to report new onset or worsening of existing constipation promptly to their physician.

Indication & usage

Phoscut (Sevelamer Carbonate 400/800 mg) is a phosphate binder indicated in Hyperphosphatemia for the control of serum phosphorus in patients with Chronic Kidney Disease on dialysis.

Dosage & administration

Patient must take Phoscut three times a day with meals.

Phoscut dose is concluded depending upon the serum phosphorus levels in the body.

Serum Phosphorus	Phoscut 400 mg
>4.5 and <5.5 mg / dL	1 tablet three times daily with meals
>5.5 and <7.5 mg / dL	2 tablets three times daily with meals
>7.5 mg / dL	4 tablets three times daily with meals

 

Serum Phosphorus	Phoscut 800 mg
>5.5 and <7.5 mg / dL	1 tablets three times daily with meals
>7.5 mg / dL	2 tablets three times daily with meals

Starting Dose for Dialysis Patients Switching From Calcium Acetate to Phoscut

Calcium Acetate 667 mg (Tablets per meal)	Phoscut 800 mg (Tablets per meal)
1 tablet	1 tablet
2 tablets	2 tablets
3 tablets	3 tablets

Presentation:

Phoscut 400: 10 tablets packed in a blister strip, 5 such strips packed in a carton

Phoscut 800: 10 tablets packed in a blister strip, 5 such strips packed in a carton