Calcium Acetate
Calcium acetate is an **oral phosphorus binding agent** primarily utilized in the management of hyperphosphatemia secondary to **chronic kidney disease (CKD)**. > **Clinical Pearl:** Calcium acetate is considered the most efficacious calcium-based phosphate binder. It binds approximately twice as much phosphorus per gram of elemental calcium compared to calcium carbonate, resulting in a lower risk of iatrogenic hypercalcemia. Furthermore, unlike calcium citrate, it does not enhance gastrointestinal absorption of aluminum.
Mechanism: When administered with meals, calcium acetate dissociates in the gastrointestinal tract. The calcium ions then bind to dietary phosphorus in the stomach and proximal small intestine to form **calcium phosphate**, an insoluble complex. Dietary Phosphorus + Calcium Acetate → **Insoluble Calcium Phosphate** → Excreted in feces. This mechanism effectively reduces the gastrointestinal absorption of phosphorus, thereby lowering serum phosphorus levels. It is soluble over a wide range of pH, making it highly available for binding.
Dosing by species
- Hyperphosphatemia associated with chronic renal failure · 60-90 mg/kg/day · PO · divided with meals · In conjunction with a low-phosphorus diet. Give with food or mixed with food, or just prior to each meal. Individualize dose to achieve desired serum phosphorus concentrations. Decrease dose if serum calcium exceeds normal limits.
- Hyperphosphatemia in CKD · 60-90 mg/kg/day divided · PO · divided with meals · Long-term · Dose must be titrated based on serum phosphorus levels. Must be given with food.
- Hyperphosphatemia associated with chronic renal failure · 60-90 mg/kg/day · PO · divided with meals · In conjunction with a low-phosphorus diet. Give with food or mixed with food, or just prior to each meal. Individualize dose to achieve desired serum phosphorus concentrations. Decrease dose if serum calcium exceeds normal limits.
- Hyperphosphatemia in CKD · 60-90 mg/kg/day divided · PO · divided with meals · Long-term · Dose must be titrated based on serum phosphorus levels. Must be given with food.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Routes of administration
Contraindications
- Pre-existing hypercalcemia
Adverse effects
- Hypercalcemia
- Gastrointestinal intolerance (nausea)
Drug interactions
- Calcitriol · May lead to hypercalcemia; if used concomitantly, intensified monitoring for hypercalcemia is mandatory.
- Digoxin · Not recommended; hypercalcemia induced by calcium acetate may cause serious arrhythmias in patients on digoxin.
- Fluoroquinolones · Oral calcium can reduce the absorption of fluoroquinolones. Separate dosages by at least two hours. · major
- Tetracyclines · Oral calcium can reduce the absorption of tetracyclines. Separate dosages by at least two hours. · major
- Levothyroxine · Decreased absorption of levothyroxine · moderate
Monitoring
- Serum phosphorus (after a 12-hour fast)
- Serum ionized calcium
- Monitor initially at 10-14 day intervals; once 'stable', at 4-6 week intervals
Overdose
Acute overdoses could potentially cause **hypercalcemia**. - **Management:** Patients should be monitored and treated symptomatically. - If the dosage was massive and recent, consider using standard protocols to empty the gut (e.g., emesis induction or gastric lavage, followed by activated charcoal, though charcoal does not bind minerals well).
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.