Epinephrine and Levothyroxine and liothyronine interaction
Epinephrine and Levothyroxine and liothyronine: both prescribing labels flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Levothyroxine and liothyronine (NP Thyroid 60) label · effective 2026-01-01
Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects.
From the Epinephrine label · effective 2026-07-06
• Drugs that potentiate the effects of epinephrine include sympathomimetics, beta blockers, tricyclic antidepressants, MAO inhibitors, COMT inhibitors, clonidine, doxapram, oxytocin, levothyroxine sodium, and certain antihistamines.
…[see Warnings and Precautions (5.6) and Adverse Reactions (6) ]. β-blockers, such as propranolol Cyclopropane or halogenated hydrocarbon anesthetics, such as halothane Antihistamines Thyroid hormones Diuretics Cardiac glycosides, such as digitalis glycosides Quinidine Drugs potentiating hypokalemic effects of epinephrine • Potassium depleting diuretics • Corticosteroids…
• Drugs that increase the arrhythmogenic potential of epinephrine include beta blockers, cyclopropane and halogenated hydrocarbon anesthetics, quinidine, antihistamines, exogenous thyroid hormones, diuretics, and cardiac glycosides.
• β-blockers, such as propranolol • Cyclopropane or halogenated hydrocarbon anesthetics, such as halothane • Antihistamines • Thyroid hormones • Diuretics • Cardiac glycosides, such as digitalis glycosides • Quinidine Drugs potentiating arrhythmogenic effects of epinephrine.
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Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.