Diphenhydramine and Metoprolol: Drug Interaction Guide

Quick answer: This combination requires caution. Diphenhydramine and Metoprolol can be used together with adjustments and monitoring.

Interaction severity: Moderate — caution required

How Diphenhydramine interacts with Metoprolol

Diphenhydramine is a moderate CYP2D6 inhibitor that decreases metoprolol metabolism, increasing exposure and risk of bradycardia and hypotension.

What you should do

Monitor heart rate and blood pressure; consider a non-sedating antihistamine (cetirizine, loratadine) or switch beta-blocker to bisoprolol.

Key facts

Severity

Moderate — caution required

Mechanism

Diphenhydramine is a moderate CYP2D6 inhibitor that decreases metoprolol metabolism, increasing exposure and risk of bra...

Action

Monitor heart rate and blood pressure; consider a non-sedating antihistamine (cetirizine, loratadine) or switch beta-blo...

Important medical disclaimer: This page provides educational information about drug interactions for general reference. It is not a substitute for professional medical advice, diagnosis, or treatment. Always discuss your specific medications with a qualified healthcare provider before starting, stopping, or changing any treatment. About our editorial team.

Frequently asked questions

Can I take Diphenhydramine and Metoprolol together?

With caution. Monitor heart rate and blood pressure; consider a non-sedating antihistamine (cetirizine, loratadine) or switch beta-blocker to bisoprolol.

What is the severity of this interaction?

The interaction between Diphenhydramine and Metoprolol is classified as Moderate — caution required. Diphenhydramine is a moderate CYP2D6 inhibitor that decreases metoprolol metabolism, increasing exposure and risk of bradycardia and hypotension.

What should I do if I'm prescribed both?

Monitor heart rate and blood pressure; consider a non-sedating antihistamine (cetirizine, loratadine) or switch beta-blocker to bisoprolol. Always consult your prescribing clinician — do not stop or change medications without medical guidance.

Last reviewed: by iMedic Medical Editorial Team. Our editorial process.