Calcium Acetate

What is calcium acetate?

Calcium acetate (brand names: PhosLo®, Calphron®, Eliphos®) is a phosphate binder. It attaches itself to phosphorus in the intestine, preventing it from being absorbed. This medication is primarily used in patients with chronic kidney disease, as abnormally high phosphate levels occur with this disease.

It is used off label (extra label) in veterinary medicine. Many drugs are commonly prescribed for off-label use in veterinary medicine. “Off label” means the drug is being used in a way that has not been reviewed or approved by the U.S. Food and Drug Administration (FDA) or Health Canada. 

In these instances, follow your veterinarian’s directions and cautions carefully, as they may be significantly different from those on the label.

How is calcium acetate given?

• Calcium acetate is given by mouth in the form of a tablet, capsule, or liquid solution.
• It should be given with meals. Your veterinarian may prescribe additional doses between meals.
• Measure liquids carefully.
• Follow your veterinarian’s instructions on administering this medication carefully and give for the entire time prescribed by your veterinarian, even if your pet is feeling better.

This medication should take effect within 1 to 2 hours; however, effects may not be noted outwardly, so laboratory tests may be needed to evaluate this medication’s effectiveness.

What if I miss giving my pet the medication?

If you miss a dose, give it as soon as you remember, and then continue with the regular dosing schedule. However, if it is almost time for the next dose, skip the missed dose and resume the regular dosing schedule. Do not give the pet two doses at once.

Are there any potential side effects?

Calcium acetate may cause the following side effects:

• Elevated blood calcium levels
• Calcium deposits in soft tissues
• Nausea, vomiting

Serious adverse reactions may occur. If any of the following signs develop, stop giving calcium acetate and contact your veterinarian immediately:

• An allergic reaction such as irregular breathing, rash, fever, puffiness and swelling around the face

Drug sensitivities can develop over time with repeated exposure. Your pet may have no reaction after the first few doses, but may develop a sensitivity later. It is important to watch for signs of an allergic reaction over the entire course of treatment.

Other side effects may occur. If you notice anything unusual, contact your veterinarian immediately. This short-acting medication should stop working within 24 hours, although the effects can be longer in pets with liver or kidney disease.

Are there any risk factors for this medication?

DO NOT USE calcium acetate in:

• Pets that are allergic to any component
• Pets with high blood calcium levels

USE WITH CAUTION in:

• Pets that are pregnant or nursing

Are there any drug interactions I should be aware of?

Several medications should be used with caution when given with calcium acetate, including:

• Aspirin
• Atenolol
• Calcitriol
• Calcium channel blockers (e.g., amlodipine)
• Cefpodoxime, ceftriaxone
• Chlorothiazide
• Digoxin
• Fluoroquinolones
• Iron
• Ketoconazole
• Levothyroxine
• Sucralfate
• Tetracyclines
• Verapamil

Be sure to tell your veterinarian about any medications (including vitamins, supplements, or herbal therapies) that your pet is taking before starting any treatment.

Is any monitoring needed with this medication?

• Serum ionized calcium and phosphorus levels should be monitored every 2 to 6 weeks while initially using this medication, depending on the patient. If stable, these levels can be measured every 3 months. Phosphorus should be measured after your pet has fasted for 12 hours.
• At home, monitor for any side effects such as those noted above. If any occur, stop using the medication and contact your veterinarian.

How do I store calcium acetate?

• Store this medication at room temperature, around 77°F (25°C).
• Keep medication out of reach of children and pets.

What should I do in case of emergency?

If you suspect an overdose or an adverse reaction to the medication, call your veterinary office immediately. If they are not available, follow their directions in contacting an emergency facility. Be prepared to provide information about the product and your pet's weight and symptoms. Report any adverse effects to the FDA or Health Canada.