Drug interactions
Dihydroergotamine + Isoniazid
Severity: Major
Dihydroergotamine 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
Dihydroergotamine levels rise when CYP3A4 is inhibited, risking ergotism with severe peripheral vasospasm and ischemia. Isoniazid is a weaker CYP3A4 inhibitor than agents named in the labeling contraindication, but the toxicity is serious.
What this interaction means in plain words
Dihydroergotamine 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.
Dihydroergotamine belongs to Central Nervous System; Isoniazid belongs to Anti Bacterial.
Why it happens
Inhibition of CYP3A4 metabolism of dihydroergotamine.
What to do
Avoid if possible and choose an alternative migraine therapy during isoniazid treatment. If used, monitor for numbness, coldness, or pain in the extremities and stop at the first signs of ischemia.
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 Dihydroergotamine
- Almotriptan + Dihydroergotamine Contraindicated
- Clarithromycin + Dihydroergotamine Contraindicated
- Dihydroergotamine + Dopamine Contraindicated
- Dihydroergotamine + Dronedarone Contraindicated
- Dihydroergotamine + Efavirenz Contraindicated
- Dihydroergotamine + Eletriptan Contraindicated
Frequently asked questions
Can I take Dihydroergotamine with Isoniazid?
MediHelp rates the interaction as major. Dihydroergotamine 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. Dihydroergotamine levels rise when CYP3A4 is inhibited, risking ergotism with severe peripheral vasospasm and ischemia. Isoniazid is a weaker CYP3A4 inhibitor than agents named in the labeling contraindication, but the toxicity is serious.
How serious is the interaction between Dihydroergotamine 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 if possible and choose an alternative migraine therapy during isoniazid treatment. If used, monitor for numbness, coldness, or pain in the extremities and stop at the first signs of ischemia.
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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