Phoscut

For the use of a Registered Medical Practitioner, Hospital or Laboratory only.

1. Description

Phoscut contains 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.

2. Composition

Phoscut 400 – Sevelamer Carbonate 400 mg

Phoscut 800 – Sevelamer Carbonate 800 mg

3. Dosage Form

Tablet

4. Pharmacology

Patients with CKD retain phosphorus and can develop Hyperphosphataemia. 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. Hyperphosphataemia plays a role in the development of secondary hyperparathyroidism in renal insufficiency.

Management of Hyperphosphataemia 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.

Pharmacodynamics

Phoscut contains sevelamer carbonate, a non-absorbed, cross-linked polymeric amine that binds dietary phosphate within the gastrointestinal tract. After oral administration, the amine groups become protonated in the intestine and bind phosphate through ionic and hydrogen bonding. The resulting phosphate–sevelamer complex is not absorbed and is excreted in the faeces, thereby reducing intestinal phosphate absorption and lowering serum phosphorus concentrations.

In patients with chronic kidney disease (CKD), impaired renal phosphate excretion leads to hyperphosphataemia, which contributes to secondary hyperparathyroidism, renal osteodystrophy, and vascular calcification. By lowering serum phosphate levels, sevelamer helps improve mineral metabolism and reduces the calcium-phosphorus product without increasing calcium load

Pharmacokinetics

Absorption

Sevelamer carbonate is not absorbed from the gastrointestinal tract. Its phosphate-binding action is confined to the intestinal lumen, and systemic exposure is negligible.

Distribution

As sevelamer is not systemically absorbed, it has no clinically significant systemic distribution. Its activity is limited to the gastrointestinal tract.

Metabolism

Sevelamer carbonate is not metabolized. It remains chemically unchanged while binding phosphate in the gastrointestinal tract.

Elimination

The phosphate-bound sevelamer complex is eliminated unchanged in the faeces. Since the drug is not absorbed, renal excretion is negligible, and no active metabolites are formed.

5. Indications

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

6. Contraindications

Phoscut is contraindicated in patients with bowel obstructions.

7. Precautions

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

8. Drug Interactions

It may develop drug interaction with the following drugs

• Ciprofloxacin
• Digoxin
• Warfarin
• Enalapril
• Metoprolol
• Iron

9. Adverse Effects

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.

10. 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.

Starting Dose for Dialysis Patients Switching From Calcium Acetate to Phoscut

11. 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.

12. Storage

Store in a dry place at a temperature not exceeding 30°C. Protect from light. Keep the medicine out of reach of children.

Additional Information

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).

13. Presentation

Phoscut 800 mg – 10 tablets in a strip, 5 strips in a Box.

Phoscut 400 mg – 10 tablets in a strip, 5 strips in a Box.