Drug interactions
Ergotamine + Isoniazid
Severity: Major
Ergotamine and Isoniazid: major 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
Ergotamine levels rise when CYP3A4 is inhibited, and this can lead to ergotism with severe peripheral vasospasm and ischemia. Isoniazid is a weaker CYP3A4 inhibitor than macrolides or azoles, but the potential toxicity is serious.
What this interaction means in plain words
Ergotamine and Isoniazid can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Ergotamine belongs to Central Nervous System; Isoniazid belongs to Anti Bacterial.
Why it happens
Isoniazid inhibits CYP3A4, reducing ergotamine clearance.
What to do
Avoid the combination where possible and use a non-ergot migraine treatment. If used, counsel the patient to report numbness, coldness or pain in the limbs promptly.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Isoniazid
Other interactions of Ergotamine
- Almotriptan + Ergotamine Contraindicated
- Atazanavir + Ergotamine Contraindicated
- Clarithromycin + Ergotamine Contraindicated
- Cobicistat + Ergotamine Contraindicated
- Darunavir + Ergotamine Contraindicated
- Dihydroergotamine intranasal + Ergotamine Contraindicated
Frequently asked questions
Can I take Ergotamine with Isoniazid?
MediHelp rates the interaction as major. Ergotamine and Isoniazid can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Ergotamine levels rise when CYP3A4 is inhibited, and this can lead to ergotism with severe peripheral vasospasm and ischemia. Isoniazid is a weaker CYP3A4 inhibitor than macrolides or azoles, but the potential toxicity is serious.
How serious is the interaction between Ergotamine and Isoniazid?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination where possible and use a non-ergot migraine treatment. If used, counsel the patient to report numbness, coldness or pain in the limbs promptly.
What other medicines interact with Isoniazid?
MediHelp also lists interactions of Isoniazid with, for example, Bacillus calmette-guerin substrain tice, Benzhydrocodone / acetaminophen, Carbamazepine. The full list is on the Isoniazid page.
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