What to Do When Calcium Supplements Cause Constipation

NOVEMBER 15, 2016
Individuals reach peak bone mass around their early 20s, after which bone mass is lost faster than it is created.1 Thus, as an individual ages, the risk for osteoporosis increases. If age is a nonmodifiable risk factor, what can an individual do to prevent osteoporosis? 
In addition to doing weight-bearing exercises or muscle-strengthening exercises to build and maintain bone density, it’s important to get enough calcium and vitamin D.
I’ve filled a lot of calcium with vitamin D supplements for elderly patients. A couple of weeks ago, I encountered a prescription for a calcium supplement and a prescription for a constipation medication. One of the adverse effects of calcium supplements is constipation, so I instantly knew that the calcium supplement was most likely causing the constipation. 
In pharmacy school, I was taught to see if there was a cause when I learned of a patient’s adverse reaction, because if I’m treating the problem without removing the cause, the problem will still persist. In this situation, I couldn’t remove the cause. If I were to request that the doctor stop prescribing the calcium supplements, the elderly patient would be at higher risk for osteoporosis. If I can’t remove the cause, what can I do in this type of situation?
Although calcium carbonate is the cheapest calcium supplement option, it’s also the most constipating.2 If cost is an issue, I could recommend that the patient try a few different brands; if cost isn’t an issue, I could recommend that the patient try a few different types of calcium supplements to find which one the patient tolerates best.2 I could show the patient how to read the label to determine which has lower calcium per dose, as lower dose calcium supplements may be better tolerated.3 Although this may mean being dosed more than one time per day to achieve the prescribed dosage, spreading out the calcium doses throughout the day may mean better tolerance.4 Taking the supplements with meals may also help.4 Many patients taking calcium supplements are over age 50 and may be taking acid blockers such as Zantac (ranitidine), Protonix (pantoprazole), or Prilosec (omeprazole). These patients have low stomach acid, which is an issue for calcium carbonate because it relies on stomach acid for absorption. Although not the cheapest calcium supplement option, calcium citrate is recommended for these patients.
Patients can benefit from nonpharmacological advice. Regardless of which calcium supplement the patient is taking, there may still be the possibility of constipation. Patients should be counseled to drink plenty of water, increase their dietary fiber intake, and be physically active to minimize this possibility.3

1. Osteoporosis. Mayo Clinic website. mayoclinic.org/diseases-conditions/osteoporosis/symptoms-causes/dxc-20207860. Accessed November 16, 2016.
2. Nutrition and healthy eating. Mayo Clinic website. mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/calcium-supplements/art-20047097?pg=2. Accessed November 16, 2016.
3. All about calcium supplements. New York State Department of Health website. health.ny.gov/publications/1980/index.htm. Accessed November 16, 2016.
4. National Institutes of Health. Calcium: dietary supplement fact sheet. NIH website. ods.od.nih.gov/factsheets/Calcium-HealthProfessional. Accessed November 16, 2016.

Catherine Duong, PharmD Candidate
Catherine Duong is currently working towards a Doctor of Pharmacy (Pharm.D.) degree at Midwestern University - Glendale. She is passionate about and takes pride in working in the community through education and community outreach. She enjoys working for non-profit organizations and continues to seek new opportunities to learn and contribute more in the community. You can follow her on Twitter @Catherine_Duong.