Dihydroergotamine Injection and Idelalisib: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Idelalisib
Dihydroergotamine Injection
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased dihydroergotamine exposure and an increased risk of acute ergot toxicity
Interaction Deep Dive
Coadministration of dihydroergotamine with other potent CYP3A4 inhibitors have resulted in vasospasm, cerebral ischemia, and ischemia of the extremities. Due to the potential for acute ergot toxicity, concomitant use of dihydroergotamine and a strong CYP3A4 inhibitor such as idelalisib is contraindicated21.
Why it happens (mechanism)
Inhibition of CYP3A-mediated metabolism of dihydroergotamine
Literature reports
1 report — tap to read
a) There have been a few reports of serious adverse events associated with the coadministration of dihydroergotamine and potent CYP3A4 inhibitors, resulting in vasospasm that led to cerebral ischemia and/or ischemia of the extremities 1.
Common questions
Can I take Dihydroergotamine Injection and Idelalisib together?
Increased dihydroergotamine exposure and an increased risk of acute ergot toxicity Always confirm with your pharmacist or prescriber before making any change.
How serious is the Dihydroergotamine Injection and Idelalisib interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "unspecified". The timing of this interaction is not well characterized.
How strong is the evidence for this interaction?
The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
Questions for your pharmacist
- Does my dose of Dihydroergotamine Injection or Idelalisib need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (2)
- Product Information: Migranal(R) nasal spray, dihydroergotamine mesylate nasal spray. Bausch Health US LLC (per FDA), Bridgewater, NJ, 2022. DailyMed
- Product Information: D.H.E. 45(R) intravenous injection, intramuscular injection, subcutaneous injection, dihydroergotamine mesylate intravenous injection, intramuscular injection, subcutaneous injection. Valeant Pharmaceuticals North America (per DailyMed), Aliso Viejo, CA, 2012.
Keep reading about Idelalisib
Keep reading about Dihydroergotamine Injection
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