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Generic name: calcium acetateKAL-see-um-AS-e-tate ]
Brand names: Calphron, Phoslyra
Drug classes: Minerals and electrolytes, Phosphate binders

Medically reviewed by on Dec 21, 2023. Written by Cerner Multum.

What is Phoslyra?

Calcium is a mineral that is needed for many functions of the body, especially bone formation and maintenance. Calcium can also bind to other minerals such as phosphate, and aid in their removal from the body.

Phoslyra is used to control phosphate levels to keep them from getting too high in people with kidney failure who are on dialysis.

Phoslyra may also be used for purposes not listed in this medication guide.

Phoslyra side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Phoslyra may cause serious side effects. Stop using Phoslyra and call your doctor at once if you have:

Common side effects of Phoslyra may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


You should not use Phoslyra if you have high levels of calcium in your blood.

Before taking this medicine

You should not use Phoslyra if you are allergic to it, or if you have high levels of calcium in your blood.

Tell your doctor if:

Tell your doctor if you are pregnant or plan to become pregnant. It is not known whether Phoslyra will harm an unborn baby, but having kidney failure or developing hypercalcemia during pregnancy may cause complications in the baby and the mother. The benefit of using this medicine during pregnancy may outweigh any risks..

Tell your doctor if you are breastfeeding.

Phoslyra is not approved for use by anyone younger than 18 years old.

How should I take Phoslyra?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Take the capsule with food.

You may need to keep a food diary to measure how much calcium you are getting in your diet.

You may need frequent medical tests. Even if you have no symptoms, tests can help your doctor determine if Phoslyra is effective.

Store at room temperature away from moisture and heat.

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking Phoslyra?

Do not take additional calcium supplements unless your doctor has told you to.

Ask your doctor before using an antacid, and use only the type your doctor recommends. Some antacids contain calcium.

What other drugs will affect Phoslyra?

If you take any of the following medicines, take them separately from your dose of calcium acetate:

Other drugs may affect Phoslyra, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.