Drug interactions
Dihydroergotamine intranasal + Phenylephrine
Severity: Major
Dihydroergotamine intranasal and Phenylephrine: 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
Phenylephrine is an alpha-1 agonist vasoconstrictor and dihydroergotamine also constricts blood vessels, so combined use can produce marked vasoconstriction and a rise in blood pressure. Peripheral or cerebral ischemia is possible, especially with systemic phenylephrine exposure.
What this interaction means in plain words
Dihydroergotamine intranasal and Phenylephrine 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
Additive pharmacodynamic vasoconstriction through alpha-adrenergic agonism and ergot-mediated serotonergic and adrenergic vascular effects.
What to do
Avoid systemic or repeated use of phenylephrine with dihydroergotamine; choose a non-vasoconstrictor alternative. If unavoidable, monitor blood pressure and watch for ischemic symptoms.
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 Phenylephrine
- Isocarboxazid + Phenylephrine Contraindicated
- Phenelzine + Phenylephrine Contraindicated
- Phenylephrine + Tranylcypromine Contraindicated
- Bromocriptine + Phenylephrine Major
- Cocaine + Phenylephrine Major
- Dihydroergotamine + Phenylephrine Major
Frequently asked questions
Can I take Dihydroergotamine intranasal with Phenylephrine?
MediHelp rates the interaction as major. Dihydroergotamine intranasal and Phenylephrine 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. Phenylephrine is an alpha-1 agonist vasoconstrictor and dihydroergotamine also constricts blood vessels, so combined use can produce marked vasoconstriction and a rise in blood pressure. Peripheral or cerebral ischemia is possible, especially with systemic phenylephrine exposure.
How serious is the interaction between Dihydroergotamine intranasal and Phenylephrine?
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 systemic or repeated use of phenylephrine with dihydroergotamine; choose a non-vasoconstrictor alternative. If unavoidable, monitor blood pressure and watch for ischemic symptoms.
What other medicines interact with Phenylephrine?
MediHelp also lists interactions of Phenylephrine with, for example, Isocarboxazid, Phenelzine, Tranylcypromine. The full list is on the Phenylephrine page.
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