Drug interactions
Diphenhydramine + Phenylephrine po
Severity: Minor
Diphenhydramine and Phenylephrine po: 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
Oral phenylephrine is a decongestant with mild stimulant activity and is frequently combined with antihistamines in cold products. The sedative and stimulant effects may offset one another, and the combination is generally well tolerated.
What this interaction means in plain words
Diphenhydramine and Phenylephrine po have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised.
Why it happens
Opposing CNS effects of an H1 antihistamine and a sympathomimetic; no significant pharmacokinetic interaction.
What to do
No specific action is needed. Monitor blood pressure in hypertensive patients and in older men with urinary retention.
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 Diphenhydramine
Frequently asked questions
Can I take Diphenhydramine with Phenylephrine po?
MediHelp rates the interaction as minor. Diphenhydramine and Phenylephrine po have a small, usually unimportant interaction. Most people can take both; the pharmacist may still mention it so that any unexpected effect is recognised. Oral phenylephrine is a decongestant with mild stimulant activity and is frequently combined with antihistamines in cold products. The sedative and stimulant effects may offset one another, and the combination is generally well tolerated.
How serious is the interaction between Diphenhydramine and Phenylephrine po?
MediHelp rates it minor, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: No specific action is needed. Monitor blood pressure in hypertensive patients and in older men with urinary retention.
What other medicines interact with Diphenhydramine?
MediHelp also lists interactions of Diphenhydramine with, for example, Alfentanil, Belladonna and opium, Benzhydrocodone / acetaminophen. The full list is on the Diphenhydramine page.
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