Calcium Acetate
Calcium acetate
Also known as: PhosLo · Calphron · Eliphos · Phosex · calcii acetas · acetato de calcio · kalcio acetates · kalciumacetat · kalciumasetaatti · Calcium diacetate
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Hyperphosphatemia associated with chronic renal failure | 60-90 mg/kg/day | PO | divided with meals | — | 🌎 NA |
| Hyperphosphatemia in CKD | 60-90 mg/kg/day divided | PO | divided with meals | Long-term | 🌍 EU |
- Hyperphosphatemia associated with chronic renal failure: 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: Dose must be titrated based on serum phosphorus levels. Must be given with food.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Hyperphosphatemia associated with chronic renal failure | 60-90 mg/kg/day | PO | divided with meals | — | 🌎 NA |
| Hyperphosphatemia in CKD | 60-90 mg/kg/day divided | PO | divided with meals | Long-term | 🌍 EU |
- Hyperphosphatemia associated with chronic renal failure: 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: 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.
Overview
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 of action
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.
Safety & warnings
Contraindications
- Pre-existing hypercalcemia
Adverse effects
- Hypercalcemia
- Gastrointestinal intolerance (nausea)
Precautions
Warning: Do not use in patients with pre-existing hypercalcemia.
- Ca × P Product: Use with extreme caution if the serum calcium and phosphorus product exceeds 60 due to the risk of metastatic soft tissue mineralization.
- Concurrent Calcitriol: The concurrent use of calcium-based binders and calcitriol is controversial; some consider it contraindicated, while others require intensified monitoring for hypercalcemia.
- Monitoring: Adequate monitoring of serum ionized calcium and phosphorus is strictly required.
Drug interactions
May lead to hypercalcemia; if used concomitantly, intensified monitoring for hypercalcemia is mandatory.
Not recommended; hypercalcemia induced by calcium acetate may cause serious arrhythmias in patients on digoxin.
Oral calcium can reduce the absorption of fluoroquinolones. Separate dosages by at least two hours.
Oral calcium can reduce the absorption of tetracyclines. Separate dosages by at least two hours.
Decreased absorption of levothyroxine
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
Pharmacokinetics
Absorption
In humans, approximately 30% is absorbed when given with food. No specific pharmacokinetic information is available for dogs and cats.
Elimination
Unabsorbed calcium and bound calcium phosphate are eliminated in the feces.
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).
Available products
Formulations
- Tablets
- Capsules
- Gelcaps
Human-labeled
- Calcium Acetate Oral Tablets: 667 mg (169 mg elemental calcium); Calphron® (Nephro-Tech); Eliphos® (Hawthorn)
- Calcium Acetate Oral Capsules & Gelcaps: 667 mg (169 mg elemental calcium); PhosLo® (Fresenius)
Regulatory status
Human approved products used off-label
POM (Prescription Only Medicine)
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store commercially available tablets, capsules, and gelcaps at room temperature (25°C); excursions are permitted to 15-30°C.
Client information
- Administration: Must be given with meals (either just before eating or mixed into the food) to effectively bind the phosphorus in the diet.
- Extra Doses: Do not give between meals unless specifically instructed by your veterinarian (this is sometimes done if the pet needs extra calcium, but usually it's only for binding phosphorus in food).
- Monitoring: Your pet will require ongoing laboratory monitoring (blood tests) to ensure calcium and phosphorus levels remain in a safe range.
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.