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Problems with Calcium Supplements


Too much calcium from supplements can cause problems. Be sure that you do not take more than 500–600 mg at one time and do not exceed 1,000–1,200 mg per day.

Calculate the amount of calcium you get in your diet and add supplements only up to your daily requirement.

  • Acid rebound. Calcium carbonate may cause acid rebound where the stomach overcompensates for the high dose of calcium carbonate, which is alkaline, by churning out more acid.

    People with a history of stomach ulcers may have to switch to calcium citrate.
  • Constipation. Calcium supplements can have a mild binding effect but by themselves don’t usually cause serious constipation. If you take another supplement or medication that binds the stool, the addition of calcium supplements could cause a problem.

    Drink plenty of water and perhaps take a calcium supplement that includes magnesium.
  • Hypercalcemia – too much calcium. Some people have taken so much calcium that it causes hypercalcemia, an above normal level of calcium in the blood. Hypercalcemia may cause nausea, vomiting, confusion, and other neurological symptoms.

Drug interactions. Large doses of calcium can interfere with the absorption of a variety of drugs.

  • Tetracycline or quinolone antibiotic:  Avoid consuming large amounts of calcium — either in food or as a supplement — within 2–4 hours of taking the medication.
  • Oral bisphosphonates (alendronate, Fosamax, Actonel, Boniva, Atelvia): Wait at least 30 minutes after you take the medication before taking calcium.
  • Calcium-channel blockers or beta blockers: Discuss how to take your calcium with your doctor since the supplement can interfere with the effectiveness of your treatment.
  • Blood thinners: Avoid chewable forms of calcium that contain vitamin K.

Revised: 01/22/20. 
As a service to our readers, American Bone Health provides access to our library of archived content. Please note the date of the last review on all articles. No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician

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What to know about bone health
and fracture prevention during COVID-19

  • Remove fall dangers in your home.
  • Stay physically active, and at least 6 feet away from others.
  • Eat for proper nutrition, and take a supplement if needed to get enough calcium and vitamin D.
  • Stick with your osteoporosis medicines and ask your doctor for extra if you’re unable to go to the pharmacy.
  • If you are due for Reclast, there is little concern about delaying for a few weeks or months.
  • If you take Prolia or Evenity injections, don’t miss your appointment.  Some facilities offer “drive-through” injections. Check with your doctor.
  • Bone density testing can be postponed, if necessary.
  • Speak with your doctor about the possibility of telephone and video visits.

The Centers for Disease Control and Prevention has a page with steps you can take to reduce your risk of catching the virus if you have a chronic illness.

Be well. We are here for you if you have any questions.