Drug interactions
Dihydroergotamine intranasal + Isoniazid
Severity: Major
Dihydroergotamine intranasal 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
Intranasal dihydroergotamine is systemically absorbed and its clearance depends on CYP3A4. Isoniazid may increase exposure and the risk of ergot-related vasospasm and ischemia.
What this interaction means in plain words
Dihydroergotamine intranasal 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.
Why it happens
Inhibition of CYP3A4 metabolism of dihydroergotamine.
What to do
Avoid if possible and use a non-ergot alternative during isoniazid therapy. If used, monitor for peripheral ischemia and stop at the first signs.
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
Frequently asked questions
Can I take Dihydroergotamine intranasal with Isoniazid?
MediHelp rates the interaction as major. Dihydroergotamine intranasal 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. Intranasal dihydroergotamine is systemically absorbed and its clearance depends on CYP3A4. Isoniazid may increase exposure and the risk of ergot-related vasospasm and ischemia.
How serious is the interaction between Dihydroergotamine intranasal 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 use a non-ergot alternative during isoniazid therapy. If used, monitor for peripheral ischemia and stop at the first signs.
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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