Calpostella

Rx

Indications

• For the treatment of hyperkalaemia associated with anuria or severe oliguria, in patients requiring dialysis and in patients on regular haemodialysis or on prolonged peritoneal dialysis.

Dosage

• The dosage recommendations detailed below are a guide only; the precise requirements should be decided on the basis of regular serum electrolyte determinations.
• Adults, including the elderly:
  Oral
  The usual dose is 15 g three or four times a day. Each dose should be given as a suspension in a small amount of water or, for greater palatability, in syrup (but not fruit juices which contain potassium), in the ratio of 3 to 4 ml per gram of resin. Administer calcium polystyrene sulfonate at least 3 hours before or 3 hours after other oral medications. For patients with gastroparesis, a 6 hour separation should be considered.
  Rectal
  This route should be reserved for the patient who is vomiting or who has upper gastrointestinal tract problems, including paralytic ileus. It may be used simultaneously with the oral route for more rapid initial results or in patients with gastroparesis, who have other orally administered medications that are administered within 6 hours of calcium polystyrene sulfonate. The resin may be given rectally as a suspension of 30 g resin in 150 ml of water or 10% dextrose, as a daily retention enema. In the initial stages, administration by this route as well as orally may help to achieve a rapid lowering of the serum potassium level.
  The enema should if possible be retained for at least 9 hours, then the colon should be irrigated to remove the resin. If both routes are used initially it is probably unnecessary to continue rectal administration once the oral resin has reached the rectum.
  Children
  There are insufficient data to demonstrate the efficacy and safety of the drug in children.

Usage

• Calpostella is for oral or rectal administration only.

• In patients with plasma potassium levels below 5 mmol/litre.
• Conditions associated with hypercalcaemia (e.g. hyperparathyroidism, multiple myeloma, sarcoidosis or metastatic carcinoma).
• History of hypersensitivity to polystyrene sulfonate resins.
• Obstructive bowel disease.
• Neonates.
• Hypersensitivity to the active substance or to any of the excipients.

• Metabolism and nutrition
  The resin may give rise to hypokalaemia and hypercalcaemia, and their related clinical manifestations.
  Cases of hypomagnesaemia have been reported.
  Hypercalcaemia has been reported in well dialysed patients receiving calcium resin, and occasionally in patients with chronic renal failure. Many patients in chronic renal failure have low serum calcium and high serum phosphate, but some, who cannot be screened out beforehand, show a sudden rise in serum calcium to high levels after therapy with calcium resin. The risk emphasises the need for adequate biochemical control.
• Gastrointestinal
  Gastric irritation, anorexia, nausea, vomiting, constipation and occasionally diarrhoea may occur. Faecal impaction following rectal administration, particularly in children and gastrointestinal concretions (bezoars) following oral administration have been reported. Gastrointestinal stenosis and intestinal obstruction have also been reported, possibly, due to co-existing pathology or inadequate dilution of the resin.
  Gastrointestinal ischemia, ischemic colitis, gastro-intestinal tract ulceration or necrosis, which could lead to intestinal perforation have been reported which is sometimes fatal.
  The majority of cases have been reported with concomitant use of sorbitol.
• Respiratory, thoracic and mediastinal
  Some cases of acute bronchitis and/or broncho-pneumonia associated with inhalation of particles of calcium polystyrene sulfonate have been described.

• Calcium polystyrene sulfonate may bind to orally administered medications, which could decrease their gastrointestinal absorption and efficacy. Avoid co-administration of calcium polystyrene sulfonate with other orally administered medications. Administer calcium polystyrene sulfonate at least 3 hours before or 3 hours after other oral medications. For patients with gastroparesis, a 6-hour separation should be considered.
• Gastrointestinal stenosis, intestinal ischemia and its complications (necrosis and perforation) may occur in patients treated with polystyrene sulfonate, especially in patients using sorbitol. Therefore, concomitant use of sorbitol with calcium polystyrene sulfonate is not recommended.
• The possibility of severe potassium depletion should be considered and adequate clinical and biochemical control is essential during treatment, especially in patients on digitalis. Administration of the resin should be stopped when the serum potassium falls to 5 mmol/litre.
• Calcium polystyrene sulfonate is not totally selective for potassium. Hypomagnesaemia and/or hypercalcaemia may occur. Accordingly, patients should be monitored for all applicable electrolyte disturbances. Serum calcium levels should be estimated at weekly intervals to detect the early development of hypercalcaemia, and the dose of resin adjusted to levels at which hypercalcaemia and hypokalaemia are prevented.
• In the event of clinically significant constipation, treatment should be discontinued until normal bowel movement has resumed.
• Magnesium-containing laxatives should not be used.
• The patient should be positioned carefully when ingesting the resin, to avoid aspiration, which may lead to bronchopulmonary complications.
• The administration of calcium polystyrene sulfonate in pregnancy and during breast feeding therefore is not advised unless, in the opinion of the physician, the potential benefits outweigh any potential risks.
• There are no specific warnings on effects on ability to drive and use machines.