Drug interactions
Olanzapine + Phenylephrine
Severity: Minor
Olanzapine and Phenylephrine: minor 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
Olanzapine blocks alpha-1 adrenergic receptors and can cause orthostatic hypotension, which phenylephrine, an alpha-1 agonist, may partly counteract. The pressor response to phenylephrine may therefore be reduced.
What this interaction means in plain words
Olanzapine and Phenylephrine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Olanzapine belongs to Central Nervous System; Phenylephrine belongs to Respiratory.
Why it happens
Pharmacodynamic antagonism at alpha-1 adrenergic receptors.
What to do
Monitor blood pressure if phenylephrine is used to treat hypotension in a patient on olanzapine, and titrate to response.
What to ask your pharmacist
- Is there anything I should notice while taking both?
- Do I need to tell my doctor at the next visit?
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Other interactions of Phenylephrine
- Isocarboxazid + Phenylephrine Contraindicated
- Phenelzine + Phenylephrine Contraindicated
- Phenylephrine + Tranylcypromine Contraindicated
- Bromocriptine + Phenylephrine Major
- Cocaine + Phenylephrine Major
- Dihydroergotamine intranasal + Phenylephrine Major
Other interactions of Olanzapine
Frequently asked questions
Can I take Olanzapine with Phenylephrine?
MediHelp rates the interaction as minor. Olanzapine and Phenylephrine have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Olanzapine blocks alpha-1 adrenergic receptors and can cause orthostatic hypotension, which phenylephrine, an alpha-1 agonist, may partly counteract. The pressor response to phenylephrine may therefore be reduced.
How serious is the interaction between Olanzapine and Phenylephrine?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure if phenylephrine is used to treat hypotension in a patient on olanzapine, and titrate to response.
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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