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Posture Side Effects

Generic Name: calcium phosphate, tribasic

Note: This document contains side effect information about calcium phosphate, tribasic. Some of the dosage forms listed on this page may not apply to the brand name Posture.

For the Consumer

Applies to calcium phosphate, tribasic: oral tablet

Get emergency medical help if you have any of these signs of an allergic reaction while taking calcium phosphate, tribasic (the active ingredient contained in Posture) hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Less serious side effects of calcium phosphate, tribasic may include:

  • nausea or vomiting;

  • decreased appetite;

  • constipation;

  • dry mouth or increased thirst; or

  • increased urination.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects.

For Healthcare Professionals

Applies to calcium phosphate, tribasic: oral tablet


Gastrointestinal side effects have included nausea in up to 9% of patients receiving calcium phosphate with vitamin D and fluoride.[Ref]


Metabolic side effects have included hyperphosphatemia and hypercalciuria. Hypercalcemia has been reported with some calcium salts; however, it has not yet been associated with the use of calcium phosphate.[Ref]

Metabolic changes associated with some calcium salts include hypercalcemia, although this has not yet been associated with the use of calcium phosphate.

Hyperphosphatemia can result from overuse.

Prolonged calcium administration of some calcium salts has rarely resulted in hypercalciuria. This may be more likely in patients with hypoparathyroidism who are receiving vitamin D.[Ref]


Cardiovascular side effects have included a single case report of systemic tricalcium phosphate crystallosis involving the heart (myocarditis and pericarditis).[Ref]


1. Hasling C, Nielsen HE, Melsen F, Mosekilde L "Safety of osteoporosis treatment with sodium fluoride, calcium phosphate and vitamin D." Miner Electrolyte Metab 13 (1987): 96-103

2. Cleghorn GJ, Tudehope DI "Neonatal intestinal obstruction associated with oral calcium supplementation." Aust Paediatr J 17 (1981): 298-9

3. Edelson GW, Kleerekoper M "Hypercalcemic crisis." Med Clin North Am 79 (1995): 79-92

4. Knowles JB, Cusson G, Smith M, Sitrin MD "Pulmonary deposition of calcium phosphate crystals as a complication of home total parenteral nutrition." JPEN J Parenter Enteral Nutr 13 (1989): 209-13

5. Chaudhuri TK, Chaudhuri TuH "Calcium phosphate colloid: possible nidus for metastatic calcification in hypercalcemia." JAMA 222 (1972): 1061

6. Breuer RI, LeBauer J "Caution in the use of phosphates in the treatment of severe hypercalcemia." J Clin Endocrinol Metab 27 (1967): 695-8

7. Reimann HA, Imbriglia JE, Ducanes T "Crystal-induced myocarditis and pericarditis." Am J Cardiol 17 (1966): 269-72

Some side effects of Posture may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

Disclaimer: Every effort has been made to ensure that the information provided is accurate, up-to-date and complete, but no guarantee is made to that effect. In addition, the drug information contained herein may be time sensitive and should not be utilized as a reference resource beyond the date hereof. This material does not endorse drugs, diagnose patients, or recommend therapy. This information is a reference resource designed as supplement to, and not a substitute for, the expertise, skill , knowledge, and judgement of healthcare practitioners in patient care. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate safety, effectiveness, or appropriateness for any given patient. does not assume any responsibility for any aspect of healthcare administered with the aid of materials provided. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the substances you are taking, check with your doctor, nurse, or pharmacist.