Headlines like “Pharmacist issues warning to anyone who takes Vitamin D” are often written to sound alarming. In reality, vitamin D is safe for most people when taken at appropriate doses, but there are some important precautions.
A pharmacist might warn about the following:
- Don’t take more than recommended unless advised by a healthcare professional. Excessive vitamin D over time can cause vitamin D toxicity, leading to high blood calcium (hypercalcemia). Symptoms may include nausea, vomiting, constipation, excessive thirst, frequent urination, confusion, and, in severe cases, kidney damage.
- Be aware of medication interactions. Vitamin D can interact with some medications, including:
- Certain diuretics (especially thiazide diuretics), which can increase the risk of high calcium levels.
- Some seizure medications, which can lower vitamin D levels.
- Glucocorticoids (steroids), which can reduce vitamin D’s effectiveness.
- Orlistat and some cholesterol-lowering medicines, which can reduce vitamin D absorption.
- People with certain medical conditions should use caution. Conditions such as kidney disease, sarcoidosis, some other granulomatous diseases, or hyperparathyroidism may require closer monitoring.
- You may not need high-dose supplements. Many adults can meet their needs with modest supplementation if recommended by their healthcare provider.
For most adults, the recommended dietary allowance (RDA) is:
- 600 IU (15 micrograms) daily for adults aged 19–70.
- 800 IU (20 micrograms) daily for adults over 70.
The tolerable upper intake level for most adults is 4,000 IU (100 micrograms) per day unless a healthcare professional recommends a higher dose for a specific medical reason.
If you’re taking vitamin D, it’s a good idea to tell your healthcare provider about all of your medications and supplements, especially if you’re taking high doses or have kidney disease or another chronic health condition.
