Calcium Supplements

What are calcium supplements?

Calcium supplements are various forms of calcium used to treat or prevent low calcium blood levels (hypocalcemia) in many species. Calcium with lactate, citrate, ascorbate, carbonate, gluconate, or phosphate may be available.

Bone meal has also been used as a calcium source, but it may contain undesirable components, and the effects are similar to the manufactured supplements. Calcium derived from coral is not recommended due to environmental concerns.

Commercially prepared diets for pets are complete and balanced, and do not need additional calcium supplementation under normal circumstances. Calcium supplements may be required when feeding a homemade diet or feeding pregnant or nursing pets. Calcium supplementation should only be used under veterinary supervision, as too much calcium can cause other health problems.

The U.S. Food and Drug Administration (FDA) does not review non-drug health products (e.g., herbals, nutraceuticals, shampoos, and other supplements) for safety or effectiveness before they are sold to the public. Manufacturers of non-drug health products must ensure their products are safe and labeled accurately. 

The FDA requires that these non-pharmaceuticals contain a disclaimer that says, “This product is not intended to diagnose, treat, cure or prevent any disease.” Health Canada licenses “veterinary health products” after reviewing safety, efficacy, and manufacturing information provided by the manufacturer. These products are not tested by Health Canada.

Your veterinarian is the best source of information about the safety of non-drug health products in pets. Just because a product is natural does not mean it is safe. All medicines and medicinal plants are potentially toxic if used inappropriately or given at high doses. Supplements can also have side effects, like pharmaceuticals. Few supplements and herbs have been subjected to rigorous scientific trials to determine their efficacy.

Although the information in this handout may be helpful, it also may be incomplete and may not represent the full range of effects the supplement could have on your pet.

How are calcium supplements given?

• Calcium supplements come in tablet, capsule, and powder forms. Injectable forms are available for use by your veterinary team in hospital.
• Tablets, capsules, and powders are given orally (by mouth).
• Calcium supplements are best given with food.
• 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 supplement should take effect within 1–2 hours, although visible effects may not be noticeable.

What if I miss giving my pet the supplement?

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 supplements may cause the following side effects:

• Constipation

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

• An allergic reaction such as irregular breathing, rash, fever, puffiness and swelling around the face
• Deficiencies of other nutrients, bone development abnormalities
• Bladder stone development, mineralization (hardening) of the soft tissues
• Changes in drinking or urination habits
• Vomiting or lack of appetite
• Weakness

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 effects may last longer in pets with kidney or liver disease.

Are there any risk factors for this supplement?

DO NOT USE calcium supplements in:

• Pets that are allergic to any component of the medication
• Pets that have high blood calcium (hypercalcemia)

USE WITH CAUTION in:

• Pets with heart disease
• Pets with kidney disease
• Pets taking digoxin or calcitriol

Are there any drug interactions I should be aware of?

The following medications should be used with caution when given with calcium supplements:

• Antacids
• Aspirin
• Azole antifungals
• Calcitriol
• Calcium channel blockers
• Cefpodoxime
• Digoxin
• Dobutamine
• Estrogens
• Fluoroquinolone antibiotics
• Levothyroxine
• Magnesium, potassium
• Neuromuscular blockers
• Phenytoin
• Propranolol
• Sucralfate
• Thiazide diuretics
• Verapamil
• Vitamin D

Vitamins, herbal therapies, and supplements have the potential to interact with each other, as well as with prescription and over-the-counter medications. Be sure to tell your veterinarian about any medications (including all vitamins, supplements, or herbal therapies) that your pet is taking before starting any new treatment.

Is any monitoring needed with this supplement?

• Your veterinarian may monitor blood calcium levels to ensure the medication is working properly.
• Follow your veterinarian’s directions for follow-up visits and diagnostics.
• At home, monitor for any abnormal changes. If any occur, discontinue the medication and contact your veterinarian.

How do I store calcium supplements?

• Store the medication at room temperature around 77°F (25°C).
• Protect from freezing.
• Keep the container 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.