Drug interactions
Epinephrine + Penbutolol
Severity: Major
Epinephrine and Penbutolol: major interaction.
Last updated Sources: US FDA label
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
Nonselective beta-blockers such as penbutolol block beta receptors, leaving epinephrine's alpha-adrenergic effects unopposed. This can cause severe hypertension with reflex bradycardia, and it may blunt epinephrine's benefit in anaphylaxis, including bronchodilation and cardiac effects.
What this interaction means in plain words
Epinephrine and Penbutolol 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
Beta-receptor blockade antagonizes epinephrine's beta effects and leaves unopposed alpha-mediated vasoconstriction.
What to do
Monitor blood pressure and heart rate closely when epinephrine is given to patients on beta-blockers. In anaphylaxis that does not respond to epinephrine, consider glucagon, and use local anesthetic epinephrine doses sparingly.
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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References
Other interactions of Epinephrine
- Epinephrine + Isocarboxazid Contraindicated
- Epinephrine + Phenelzine Contraindicated
- Epinephrine + Tranylcypromine Contraindicated
- Acebutolol + Epinephrine Major
- Amitriptyline + Epinephrine Major
- Amoxapine + Epinephrine Major
Frequently asked questions
Can I take Epinephrine with Penbutolol?
MediHelp rates the interaction as major. Epinephrine and Penbutolol 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. Nonselective beta-blockers such as penbutolol block beta receptors, leaving epinephrine's alpha-adrenergic effects unopposed. This can cause severe hypertension with reflex bradycardia, and it may blunt epinephrine's benefit in anaphylaxis, including bronchodilation and cardiac effects.
How serious is the interaction between Epinephrine and Penbutolol?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure and heart rate closely when epinephrine is given to patients on beta-blockers. In anaphylaxis that does not respond to epinephrine, consider glucagon, and use local anesthetic epinephrine doses sparingly.
What other medicines interact with Epinephrine?
MediHelp also lists interactions of Epinephrine with, for example, Isocarboxazid, Phenelzine, Tranylcypromine. The full list is on the Epinephrine page.
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