Drug interactions
Cannabidiol + Zafirlukast
Severity: Minor
Cannabidiol and Zafirlukast: minor interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Cannabidiol can inhibit CYP2C9, the main enzyme that clears zafirlukast, so zafirlukast exposure may rise. This could increase dose-related adverse effects such as headache or gastrointestinal upset, although clinical data are limited.
What this interaction means in plain words
Cannabidiol and Zafirlukast have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Cannabidiol belongs to Central Nervous System; Zafirlukast belongs to Respiratory.
Why it happens
Cannabidiol inhibits CYP2C9-mediated metabolism of zafirlukast.
What to do
Watch for increased zafirlukast adverse effects when cannabidiol is started or the dose is raised. Reduce the zafirlukast dose or consider an alternative if tolerability problems arise.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Zafirlukast
- Pimozide + Zafirlukast Contraindicated
- Lomitapide + Zafirlukast Major
- Nilotinib + Zafirlukast Major
- Warfarin + Zafirlukast Major
- Apalutamide + Zafirlukast Moderate
- Carbamazepine + Zafirlukast Moderate
Other interactions of Cannabidiol
- Cannabidiol + Phenytoin Major
- Cannabidiol + Sodium valproate Major
- Cannabidiol + Tacrolimus Major
- Abiraterone + Cannabidiol Moderate
- Alogliptin-pioglitazone + Cannabidiol Moderate
- Amiodarone + Cannabidiol Moderate
Frequently asked questions
Can I take Cannabidiol with Zafirlukast?
MediHelp rates the interaction as minor. Cannabidiol and Zafirlukast have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Cannabidiol can inhibit CYP2C9, the main enzyme that clears zafirlukast, so zafirlukast exposure may rise. This could increase dose-related adverse effects such as headache or gastrointestinal upset, although clinical data are limited.
How serious is the interaction between Cannabidiol and Zafirlukast?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Watch for increased zafirlukast adverse effects when cannabidiol is started or the dose is raised. Reduce the zafirlukast dose or consider an alternative if tolerability problems arise.
What other medicines interact with Zafirlukast?
MediHelp also lists interactions of Zafirlukast with, for example, Pimozide, Lomitapide, Nilotinib. The full list is on the Zafirlukast page.
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