Is Vitamin D Safe with Fluoxetine?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Screen for vitamin D deficiency (25-OH vitamin D) in patients on long-term fluoxetine. Target serum levels of 40–60 ng/mL. Supplement with vitamin D3 1000–2000 IU/day for maintenance or higher doses under medical supervision for deficiency correction.
Why this interaction occurs
Vitamin D receptors are found throughout the brain including areas governing serotonin synthesis (raphe nuclei). Vitamin D influences tryptophan hydroxylase expression, directly affecting serotonin production and potentially modifying SSRI efficacy. SSRI users, who often have reduced sun exposure due to depressive behavior, are at elevated risk for vitamin D deficiency, which can independently worsen mood and anxiety symptoms.
Evidence
Evidence level: moderate.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 87,365 reports mentioning Fluoxetine. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Fluoxetine + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All Vitamin D interactions → · All Fluoxetine interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.