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Can I take Colecalciferol and Tizanidine together?

Drug interaction guide

There are no known significant interactions between colecalciferol and tizanidine. It is generally considered safe to take these two medications together.

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Why this happens

Colecalciferol (Vitamin D3) is a fat-soluble vitamin processed primarily by the liver and kidneys to help the body absorb calcium. Tizanidine is a muscle relaxant that works on the central nervous system and is mainly broken down by a specific liver enzyme (CYP1A2). Because they use different pathways in the body and have different targets, they do not interfere with each other's effectiveness or safety.

You can continue to take both medications as prescribed by your doctor. As with any medication, if you notice any unusual side effects, you should mention them to your healthcare provider.

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Hypercalcaemia (high blood calcium)

Do not take colecalciferol if you have high levels of calcium in your blood or urine, or if you have severe kidney stones, as vitamin D increases calcium absorption and can worsen these conditions.

Liver impairment

Tizanidine can cause serious liver damage. You must have regular blood tests to monitor your liver function while taking this medicine.

Low blood pressure (hypotension)

Tizanidine can cause a sudden, severe drop in blood pressure, leading to dizziness or fainting. This risk is significantly increased if taken with certain blood pressure medicines or ciprofloxacin.

Stopping treatment suddenly

Do not stop taking tizanidine suddenly. Doing so can cause a rapid rise in blood pressure and heart rate. Your dose must be reduced gradually.

Alcohol

It is best to avoid or strictly limit alcohol while taking colecalciferol. Long-term heavy alcohol use can interfere with how your body absorbs and processes Vitamin D, making the treatment less effective.

It is best to avoid or strictly limit alcohol while taking tizanidine. Alcohol can significantly increase the sedative effects of this medicine, making you feel extremely drowsy or dizzy, which increases the risk of falls and accidents.

Caffeine (Coffee, Tea, Energy Drinks)

You should avoid or strictly limit caffeine while taking tizanidine. Caffeine can interfere with how your body breaks down tizanidine, leading to higher levels of the medicine in your blood. This can increase the risk of side effects like low blood pressure, a slow heart rate, or extreme drowsiness.

High-fat meals

Colecalciferol is a fat-soluble vitamin. It is best absorbed by your body when taken with a meal that contains some fat (such as eggs, avocado, nuts, or dairy).

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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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