Is Vitamin D Safe with Efavirenz?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Patients on Efavirenz should have Vitamin D (25-OH) levels monitored every 6 months. Supplementation doses higher than standard (often 2000–4000 IU/day) may be needed under medical guidance.
Why this interaction occurs
Efavirenz is a potent inducer of CYP3A4 and CYP24A1, the enzyme responsible for catabolism of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D. This leads to significantly accelerated breakdown of Vitamin D, resulting in deficiency even in patients taking standard supplement doses.
Evidence
Evidence level: strong.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 13,808 reports mentioning Efavirenz. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Efavirenz + 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 Efavirenz interactions →
Already checked this one — check your whole list
Educational only — not medical advice.
Always confirm with your doctor or pharmacist.