During cold and influenza season, many consumers elect to use various nutritional supplements marketed for immune health and support. Immune-boosting supplements may contain 1 or more of vitamins A, C, D, and E, along with trace elements of selenium and zinc. Some also contain echinacea, ginger, and other herbal ingredients for immune enhancement.

Other products marketed for immune support include prebiotics and probiotics. Some contain colostrum, which is rich in antibodies and immunoglobulins A and E that may provide immune-modulating benefits, while others may contain elderberry.1

In some cases, drug-supplement interactions can be of clinical importance but often go unrecognized by many consumers and health care professionals, according to the Handbook of Drug–Nutrient Interactions.2 As a result, a drug-supplement interaction may be a contributing factor in adverse drug effects, an increased risk of toxicities, or ineffective therapy.2 This is particularly critical in certain patient populations (see table 1).2,3



Augmenting awareness about drug-supplement interactions is critical to patient safety, ensuring optimal therapeutic effects, and preventing potential interactions. The results of some studies show that about 70% of patients taking prescription drugs do not inform their primary health care providers about their concurrent use of nutritional supplements.4 During counseling, pharmacists should encourage patients to maintain a comprehensive list of all medications, including supplements, and to adhere to manufacturer instructions and only take the recommended dosages. Pharmacists also can be instrumental in assisting patients in the proper selection of nutritional supplements and be a resource in identifying possible drug-nutrient contraindications and interactions (see table 2).5-12 Patients taking other medications and those with chronic medical conditions should always consult their primary health care providers before taking any supplements. When aiding patients seeking guidance about immune health supplements, pharmacists should also remind patients about the importance of obtaining their annual influenza vaccine during this time of year.


 

Yvette C. Terrie, BSPharm, RPh, is a consulting pharmacist and a medical writer in Haymarket, Virginia.

REFERENCES
  1. McQueen CE, Orr KK. Natural products. In: Krinsky DL, Ferreri SP, et al, eds. Handbook of Nonprescription Drugs: An Interactive Approach to Self- Care. 19th ed. Washington, DC: American Pharmacists Association; 2018.
  2. Boullata JI, Barber JR. A perspective on drug-nutrient interactions. In: Boullata JI, Armenti VT, eds. Handbook of Drug Nutrient Interactions. 1st ed. Totowa, NJ: Humana Press; 2004.
  3. Huckleberry Y, Rollins C. Essential and conditionally essential nutrients. In: Krinsky D, Berardi R, Ferreri S, et al, eds. Handbook of Nonprescription Drugs. 17th ed. Washington, DC: American Pharmacists Association; 2012.
  4. Donaldson M, Touger-Decker R. Dietary supplement interactions with medications used commonly in dentistry. J Am Dent Assoc. 2013;144(7):787-794.
  5. US Department of Health & Human Services. Vitamin C. National Institutes of Health website. ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/. Updated July 9, 2019. Accessed October 10, 2019.
  6. US Department of Health & Human Services. Vitamin A. National Institutes of Health website. ods.od.nih.gov/factsheets/VitaminA-HealthProfessional/#h9. Updated October 11, 2019. Accessed October 24, 2019.
  7. US Department of Health & Human Services. Vitamin D. National Institutes of Health website. ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/. Updated August 7, 2019. Accessed October 10, 2019.
  8. US Department of Health & Human Services. Vitamin E. National Institutes
    of Health website. ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/#h8. Accessed October 10, 2019.
  9. US Department of Health & Human Services. Zinc. National Institutes of Health website. ods.od.nih.gov/factsheets/Zinc-HealthProfessional/#h8. Updated July 10, 2019. Accessed October 10, 2019.
  10. Youdim A. Nutrient-drug interactions. Merck Manuals Professional Edition. mer- ckmanuals.com/professional/nutritional-disorders/nutrition-general-considerations/ nutrient-drug-interactions. Accessed October 10, 2019.
  11. Possible interactions with: zinc. Penn State Hershey website. pennstatehershey. adam.com/content.aspx?productid=107&pid=33&gid=000999. Accessed October 10, 2019.
  12. Possible interactions with: vitamin C (ascorbic acid). Penn State Hershey web- site. pennstatehershey.adam.com/content.aspx?productId=107&pid=33&gid=000994. Accessed October 10, 2019.
  13. Possible interactions with: vitamin C (ascorbic acid). Penn State Hershey web- site. pennstatehershey.adam.com/content.aspx?productId=107&pid=33&gid=000994. Accessed October 10, 2019.