Can I take Promethazine and Vitamin d3 together?
Drug interaction guide
Originally published 25 Jan 2026
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There are no known significant interactions between promethazine and vitamin D3 (cholecalciferol). It is generally considered safe to take these two medications together.
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Why this happens
Promethazine is an antihistamine processed primarily by the liver's cytochrome P450 enzymes, while vitamin D3 is a fat-soluble vitamin that undergoes a different metabolic pathway (hydroxylation in the liver and kidneys). They do not interfere with each other's absorption, metabolism, or effects in the body.
What you should do
You can continue to take both medications as prescribed. As with any supplement, it is best to take vitamin D3 with a meal containing some fat to help with absorption. Promethazine can cause drowsiness, so be aware of how it affects you before driving or operating machinery.
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Using other medicines
Taking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.
Disclaimer
This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.
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Article history
The information on this page is written and peer reviewed by qualified clinicians.
25 Jan 2026 | Originally published

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