Drug interactions
Phenelzine + Phenylephrine
Severity: Contraindicated
Phenelzine and Phenylephrine: contraindicated 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
Phenelzine is an irreversible MAO inhibitor, which can greatly amplify the pressor response to sympathomimetics. A hypertensive crisis may occur.
What this interaction means in plain words
Phenelzine and Phenylephrine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Phenelzine belongs to Central Nervous System; Phenylephrine belongs to Respiratory.
Why it happens
Inhibition of MAO increases availability of norepinephrine and enhances the pressor response to phenylephrine.
What to do
Avoid systemic phenylephrine in patients taking MAO inhibitors, including for two weeks after stopping. Use a non-sympathomimetic decongestant alternative.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Phenylephrine
- Isocarboxazid + Phenylephrine Contraindicated
- Phenylephrine + Tranylcypromine Contraindicated
- Bromocriptine + Phenylephrine Major
- Cocaine + Phenylephrine Major
- Dihydroergotamine intranasal + Phenylephrine Major
- Dihydroergotamine + Phenylephrine Major
Other interactions of Phenelzine
- 5-HTP + Phenelzine Contraindicated
- Amitriptyline + Phenelzine Contraindicated
- Amoxapine + Phenelzine Contraindicated
- Atomoxetine + Phenelzine Contraindicated
- Benzphetamine + Phenelzine Contraindicated
- Brimonidine + Phenelzine Contraindicated
Frequently asked questions
Can I take Phenelzine with Phenylephrine?
MediHelp rates the interaction as contraindicated. Phenelzine and Phenylephrine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Phenelzine is an irreversible MAO inhibitor, which can greatly amplify the pressor response to sympathomimetics. A hypertensive crisis may occur.
How serious is the interaction between Phenelzine and Phenylephrine?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid systemic phenylephrine in patients taking MAO inhibitors, including for two weeks after stopping. Use a non-sympathomimetic decongestant alternative.
What other medicines interact with Phenylephrine?
MediHelp also lists interactions of Phenylephrine with, for example, Isocarboxazid, Tranylcypromine, Bromocriptine. The full list is on the Phenylephrine page.
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