Over-the-Counter Case Studies: Vitamins and Supplements


CASE 1: Calcium

Q: FB is a 25 year old female looking for a daily multivitamin. She’s been taking an over-the-counter multivitamin for a year, but is considering adding calcium to her diet. FB’s mother told her she should take it to “build her bones”. FB wants to know how much she can take and if there is anything else she can do for her bone health. She is in good health with no other medical conditions. What recommendations should the pharmacist offer?

A: Calcium supplements have been shown to help prevent osteoporosis and for overall bone health. The recommended amount of calcium varies between 1000 and 1200 mg per day, depending on age. Women between the ages of 19 and 50 should take 1000 mg per day and women 50 and older should take 1200 mg per day. It is important to assess the dietary calcium intake of FB. When recommending a dose of calcium, dietary products such as milk or yogurt should be subtracted. If FB is not getting enough calcium supplements in her diet, she can take 500mg twice daily for maximum benefit. Other things she can do to build strong bones include avoiding smoking and smoking, doing weight-bearing exercises, drinking alcohol in moderation (less than one drink a day for women and less of 2 glasses a day for men) and eat healthy foods. .1

CASE 2: Vitamin D

A: LF is a 22 year old female looking for over-the-counter vitamin D. During her recent health visit, her doctor recommended that she take vitamin D as her levels are borderline low, saying it will also help her absorb calcium. LF has no medical conditions and is otherwise healthy. Because there are several formulations of vitamin D, she doesn’t know what dose to take. She takes a daily multivitamin and a calcium supplement twice a day. What recommendations should the pharmacist offer?

Q: Inform the LF that in addition to strengthening bones by aiding in the absorption of calcium, vitamin D has many other benefits. Vitamin D helps the immune system fight bacteria and viruses and also aids in muscle and nerve function.2 Most adults get vitamin D through diet and direct sunlight, but many patients still suffer from lower levels. Vitamin D is fat soluble, which means LF could overdose if she takes too much. Overdose symptoms include frequent urination, high blood sugar, nausea, vomiting, and weakness. Patients like LF, between the ages of 19 and 70, should take 600 IU of vitamin D daily. Patients over 70 should take 800 IU daily.3 Patients with vitamin D deficiency may require higher doses.

CASE 3: Zinc

A: RD is a 48-year-old man who is considering a zinc supplement to prevent COVID-19. He knows zinc is good for colds and wonders if taking it long term prevents COVID-19. RD suffers from diabetes and hypertension, but is otherwise healthy. What should the pharmacist recommend?

Q: Tell RD that several clinical trials have evaluated the use of zinc to prevent and treat COVID-19. The data are insufficient and the benefits of zinc do not outweigh the risks. Long-term use of zinc can lead to copper deficiency, which can cause anemia, ataxia, myelopathy, paresthesia, and spasticity. Therefore, RD should avoid using zinc for the prevention of COVID-19.4 The best action RD can take is to get his COVID-19 vaccines and boosters, which are very effective in preventing serious illness, hospitalization And the dead. Avoiding crowds and poorly ventilated spaces, social distancing and wearing a mask are also ways to avoid contracting COVID-19.5

CASE 4: Vitamin C

Q: SM is a 42 year old woman who asks about vitamin C supplementation and says that her friends use vitamin C topically. She takes a daily multivitamin but wants to add vitamin C to her daily regimen and asks if it is beneficial for skin health. What recommendations should the pharmacist offer?

A: Although many people use vitamin C topically for their face, many formulations also contain vitamin E. Vitamin C has been shown to protect against UV rays, and it also helps with wound healing and minimizes the formation of scars. Long-term studies on skin changes, such as wrinkles, are more difficult to assess. Because vitamin C is water soluble and used topically, it wouldn’t hurt to give it a try. Another thing SM can do for skin health is eating a balanced diet with lots of fruits and vegetables.6

About the Author

Rupal Mansukhani, PharmD, FAPhA, CTTSis an Associate Clinical Professor at Rutgers Ernest Mario School of Pharmacy, State University of New Jersey at Piscataway, and a clinical pharmacist specializing in care transitions at Morristown Medical Center in New Jersey.

Ammie Patel, PharmD, BCACP, is Clinical Assistant Professor of Pharmacy Practice and Administration at Ernest Mario School of Pharmacy at Rutgers, State University of New Jersey at Piscataway, and Ambulatory Care Specialist at RWJBarnabas Health Primary Care at Shrewsbury and Eatontown , New Jersey.


1. Overview of osteoporosis. National Institute of Arthritis and Musculoskeletal and Skin Diseases. Updated October 2019. Accessed July 4, 2022. https://www.bones.nih.gov/health-info/bone/osteoporosis/overview

2. Facts about micronutrients. CDC. Updated February 1, 2022. Accessed July 4, 2022. https://www.cdc.gov/nutrition/micronutrient-malnutrition/micronutrients/index.html

3. Vitamin D. National Institutes of Health Office of Dietary Supplements. Updated June 2, 2022. Accessed July 4, 2022. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/[RP3]

4. Zinc. National Institutes of Health. Updated April 21, 2021. Accessed July 4, 2022. https://www.covid19treatmentguidelines.nih.gov/therapies/supplements/zinc/

5. How to protect yourself and others. CDC. Updated February 25, 2022. Accessed July 4, 2022. https://www.cdc.gov/coronavirus/2019-ncov/prevent-getting-sick/prevention.html

6. Pullar JM, Carr AC, Vissers MCM. roles of vitamin C in skin health. Nutrients. 2017;9(8):866. doi:10.3390/nu9080866


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