VDC test kit slider
VDC test kit slider

The relationship between vitamin D and prescription drugs

Posted on: March 18, 2011   by  John Cannell, MD


From the Karolinska Institute in Stockholm, Sweden comes the first of what I hope will be many studies on how vitamin D affects the prescription drugs people take. Dr. Jonatan Lindh and his colleagues found that some commonly prescribed immunosuppressants have seasonal variations in their blood levels and that seasonality is directly related to vitamin D levels. It turns out that vitamin D increases levels of a key enzyme made by the liver (CYP3A4) and increased levels of CYP3A4 means that blood concentrations of certain prescription drugs will be lower.


Theoretically those drugs include a long list, including the SSRIs citalopram, escitalopram, fluoxetine, norfluoxetine and sertraline, and the antipsychotics aripiprazole, haloperidol, risperidone and ziprasidone. I only mention those because I am a psychiatrist. For a full list of drugs that may have lower blood levels because of vitamin D increasing CYP3A4, look up CYP3A4 in Wikipedia and read about the enzyme. Again, vitamin D increases the liver’s production of this vital enzyme, an enzyme which then lowers levels of the drugs it catabolizes (breaks down).

Lindh JD, Andersson ML, Eliasson E, Bjorkhem-Bergman L. Seasonal variation in blood drug concentrations and a potential relationship to vitamin D. Drug Metab Dispos. 2011 Feb 24. [Epub ahead of print] http://www.ncbi.nlm.nih.gov/pubmed/21349923


Test Your Vitamin D Levels at Home!

Our in-home Vitamin D Test Kit is easy, affordable, and an accurate way to find out your Vitamin D status.

order NOW

We need your help!

We're spreading awareness on Vitamin D Deficiency
Donate NOW
Latest Articles
Open label trial discovers 1,200 IU/day more effective than 400 IU/day in managing influenza in infants

A recent open label trial found that higher doses of vitamin D in infants reduced duration of influenza symptoms.

Weekly Newsletter