Drug interactions
Epinephrine + Timolol
Severity: Major
Epinephrine and Timolol: major interaction.
Last updated Sources: UK SmPC
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
Blocking beta-2 receptors leaves epinephrine's alpha-mediated vasoconstriction unopposed, which can cause severe hypertension with reflex bradycardia. Non-selective beta-blockers like timolol can also blunt epinephrine's effectiveness in anaphylaxis.
What this interaction means in plain words
Epinephrine and Timolol 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.
Epinephrine belongs to Endocrine; Timolol belongs to Cardiovascular.
Why it happens
Non-selective beta-blockade removes beta-2 vasodilation, leaving unopposed alpha-adrenergic effects of epinephrine.
What to do
Monitor blood pressure and heart rate when epinephrine is given to patients on timolol, and be prepared to give glucagon for anaphylaxis unresponsive to epinephrine. Consider a cardioselective beta-blocker where appropriate.
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
- Timolol Maleate 10mg Tablets - SmPC sections 4.3/4.5 (names the partner; "Local anaesthetics with added vasoconstrictors, e.g. adrenaline, should be avoided.") — electronic medicines compendium (UK SmPC)
Other interactions of Timolol
- Acebutolol + Timolol Major
- Aldesleukin + Timolol Major
- Amifostine + Timolol Major
- Amiodarone + Timolol Major
- Arformoterol + Timolol Major
- Atenolol-chlorthalidone + Timolol Major
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 Timolol?
MediHelp rates the interaction as major. Epinephrine and Timolol 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. Blocking beta-2 receptors leaves epinephrine's alpha-mediated vasoconstriction unopposed, which can cause severe hypertension with reflex bradycardia. Non-selective beta-blockers like timolol can also blunt epinephrine's effectiveness in anaphylaxis.
How serious is the interaction between Epinephrine and Timolol?
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 when epinephrine is given to patients on timolol, and be prepared to give glucagon for anaphylaxis unresponsive to epinephrine. Consider a cardioselective beta-blocker where appropriate.
What other medicines interact with Timolol?
MediHelp also lists interactions of Timolol with, for example, Acebutolol, Aldesleukin, Amifostine. The full list is on the Timolol page.
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