Medical Emergencies · single question
A patient taking IMIPRAMINE (tricyclic antidepressant) receives lidocaine with epinephrine. What cardiovascular concern arises?
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Correct answer: B. Imipramine potentiates the cardiovascular effects of epinephrine — dangerous hypertension/arrhythmia risk
✓ B) TCAs potentiate epinephrine's cardiovascular effects — dangerous interaction.
TCA (tricyclic antidepressant — imipramine, amitriptyline) + Epinephrine: TCAs block norepinephrine reuptake transporters → increased synaptic catecholamine levels → POTENTIATED response to epinephrine. Result: severe hypertension, cardiac arrhythmias (tachycardia, ventricular arrhythmias). Management: LIMIT epinephrine to 0.04mg (2 cartridges of 1:100,000) in patients on TCAs — do NOT completely avoid, but minimize. Use cardiac retraction cord (with epi) cautiously or avoid. NOTE: Sumatriptan (from the PDF question) = serotonin receptor agonist for migraines — no significant direct epi interaction, but imipramine (TCA) has this dangerous interaction.
TCA (tricyclic antidepressant — imipramine, amitriptyline) + Epinephrine: TCAs block norepinephrine reuptake transporters → increased synaptic catecholamine levels → POTENTIATED response to epinephrine. Result: severe hypertension, cardiac arrhythmias (tachycardia, ventricular arrhythmias). Management: LIMIT epinephrine to 0.04mg (2 cartridges of 1:100,000) in patients on TCAs — do NOT completely avoid, but minimize. Use cardiac retraction cord (with epi) cautiously or avoid. NOTE: Sumatriptan (from the PDF question) = serotonin receptor agonist for migraines — no significant direct epi interaction, but imipramine (TCA) has this dangerous interaction.
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