Can I take Cannabis and Clarithromycin together?
Drug interaction guide
Originally published 25 Jan 2026
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Taking clarithromycin with cannabis can significantly increase the levels of THC and CBD in your bloodstream. This can make the effects of cannabis much stronger and last longer than usual. You may experience increased drowsiness, dizziness, confusion, or a racing heart. There is also a small risk of an irregular heartbeat (heart palpitations).
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Why this happens
Your liver uses a specific enzyme (called CYP3A4) to break down cannabis. Clarithromycin 'switches off' this enzyme, which prevents your body from clearing the cannabis. This leads to a buildup of the drug in your system. Additionally, both substances can occasionally affect your heart rhythm.
What you should do
Back to contentsIt is best to avoid using cannabis while taking a course of clarithromycin. If you do choose to use both, start with a much lower dose of cannabis than usual and be aware that the effects will last longer. Seek medical help if you feel your heart racing or feel extremely dizzy.
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Using other medicines
Back to contentsTaking 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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