Vitamin D - Prometrium (Progesterone (prescription drug)) Interaction
Herbal: Vitamin D
Also Known As: Ergocalciferol, Cholecalciferol
Drug: Progesterone (prescription drug)
Brand names:
Prometrium, Endometrin, Utrogestan

Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 04, 2025
Interaction Details
Progesterone (prescription drug) is classified as belonging to the following category: Cytochrome P450 3A4 (Cyp3A4) Substrates
Vitamin D might induce CYP3A4 enzymes and reduce the bioavailability of CYP3A4 substrates.
There is some concern that vitamin D might induce CYP3A4. In vitro research suggests that vitamin D induces CYP3A4 transcription. Additionally, observational research has found that increased UV light exposure and serum vitamin D levels are associated with decreased serum levels of CYP3A4 substrates such as tacrolimus and sirolimus, while no association between UV light exposure or vitamin D levels and levels of mycophenolic acid, a non-CYP3A4 substrate, was found. A small, low-quality clinical study shows that taking vitamin D reduces levels of the CYP3A4 substrate atorvastatin and its active metabolites by up to 55%; however, the clinical effects of atorvastatin were not reduced. While researchers theorized that vitamin D might induce CYP3A4, this proposed mechanism was not specifically studied.
Interaction Rating
Likelihood of Occurrence
PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
References
- Schwartz JB. Effects of vitamin D supplementation in atorvastatin-treated patients: A new drug interaction with an unexpected consequence. Clin Pharmacol Ther 2009;85:198-203.
- Wang Z, Schuetz EG, Xu Y, Thummel KE. Interplay between vitamin D and the drug metabolizing enzyme CYP3A4. J Steroid Biochem Mol Biol 2013;136:54-8.
Vitamin D Overview

Progesterone (prescription drug) Overview
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Progesterone is used as a part of hormone replacement therapy in women who have passed menopause (the change of life) and have not had a hysterectomy (surgery to remove the uterus). Hormone replacement therapy usually includes estrogen, which is used to treat symptoms of menopause and reduce the risk of developing certain diseases. However, estrogen can also cause abnormal thickening of the lining of the uterus and increase the risk of developing uterine cancer. Progesterone helps to prevent this thickening and decreases the risk of developing uterine cancer. Progesterone is also used to bring on menstruation (period) in women of childbearing age who have had normal periods and then stopped menstruating. Progesterone is in a class of medications called progestins (female hormones). It works as part of hormone replacement therapy by decreasing the amount of estrogen in the uterus. It works to bring on menstruation by replacing the natural progesterone that some women are missing.
Vitamin D - More Interactions
Vitamin D interacts with 694 drugs
Interaction Rating Key
These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.
Major | The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur. |
Moderate | Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur. |
Minor | Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction. |
Unknown | No interactions have been reported or no interaction data is currently available. |
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Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
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Drug descriptions are provided by MedlinePlus.