Nelfinavir and Dihydroergotamine Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Nelfinavir
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 ergotism (nausea, vomiting, vasospastic ischemia)
Interaction Deep Dive
The coadministration of nelfinavir and dihydroergotamine is contraindicated as it may result in an increased exposure of dihydroergotamine. Coadministration also has the potential for serious and/or life threatening reactions such as acute ergot toxicity characterized by peripheral vasospasm and ischemia of the extremities and other tissues21. Pharmacokinetic interactions have been reported in patients treated orally with ergot alkaloids (eg, increased levels of ergotamine) and troleandomycin, presumably due to inhibition of CYP3A4 metabolism of the alkaloids by troleandomycin 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of dihydroergotamine
Literature reports
2 reports — tap to read
a) Severe ergotism related to concurrent ergotamine and protease inhibitor administration has been reported. A 40-year-old HIV-1-infected female taking nelfinavir, zidovudine, and lamiVUDine presented to her doctor with pain and cyanosis in all of her toes just one day after taking an ergotamine-containing antimigraine medication. There was no peripheral arterial pulse palpable. All symptoms resolved in 15 days. The patient took the same antimigraine medication eight months later. Cyanosis and edema of her hands and feet occurred 12 hours later. Peripheral arterial pulses were absent. The cyanosis persisted for 6 days and the pain resolved within two weeks. Ergotism is a complication of ergotamine intake with drugs that inhibit its metabolism by the liver, such as nelfinavir 3.
b) Pharmacokinetic interactions have been reported in patients treated orally with ergot alkaloids (eg, increased levels of ergotamine) and troleandomycin, presumably due to inhibition of CYP3A4 metabolism of the alkaloids by troleandomycin 1.
Common questions
Can I take Nelfinavir and Dihydroergotamine Injection together?
Increased dihydroergotamine exposure and an increased risk of ergotism (nausea, vomiting, vasospastic ischemia) Always confirm with your pharmacist or prescriber before making any change.
How serious is the Nelfinavir and Dihydroergotamine Injection interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Nelfinavir or Dihydroergotamine Injection 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 (3)
- Product Information: Migranal(R) nasal spray, dihydroergotamine mesylate nasal spray. Bausch Health US LLC (per FDA), Bridgewater, NJ, 2022. DailyMed
- Product Information: VIRACEPT(R) oral film coated tablets, oral powder, nelfinavir mesylate oral film coated tablets, oral powder. Pfizer Inc (per Dailymed), New York, NY, 2023. DailyMed
- Mortier E, Pouchot J, & Vinceneux P: Ergotism related to interaction between nelfinavir and ergotamine. Am J Med 2001; 110:594. PubMed
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