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Can I take Acetazolamide and Fybogel hi-fibre orange together?

Drug interaction guide

There is no direct chemical interaction between acetazolamide and Fybogel (ispaghula husk). However, Fybogel can potentially affect how other medicines are absorbed if taken at the exact same time. Additionally, both products can affect your body's fluid and salt levels.

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Why this happens

Fybogel is a bulk-forming fibre that can trap other medicines in the gut, potentially slowing down or reducing how much acetazolamide gets into your bloodstream. Acetazolamide is a diuretic (water tablet) that makes you lose fluid and potassium; Fybogel requires you to drink plenty of water to work properly. If you do not drink enough, the combination could lead to dehydration or constipation.

It is fine to take both, but you should space them out. Take your acetazolamide at least 1 hour before or 2 to 4 hours after taking your Fybogel. It is very important to drink at least 8 to 10 large glasses of water a day while using these together to prevent dehydration and ensure the fibre works correctly. If you feel unusually tired, dizzy, or have muscle cramps, speak to your doctor as your salt levels (like potassium) may need checking.

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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.

  • 14 Mar 2026 | Originally published
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