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Tyramine reaction
From WikEM
Contents
Background
- Occurs when patient taking a monoamine oxidase inhibitor (MAO-I) ingests tyramine
- Tyramine is a dietary amine similar to amphetamine normally metabolized by MAO
- Tyramine is a monoamine and acts indirectly to release catecholamines.
- Tyramine is typically metabolized by monoamine oxidase in the gut, a process that MAOIs interfere with.
- Tyramine is found in preserved meat, fish, cheese, alcohol, and protein-rich foods which are particularly likely to contain bacteria that convert amino acids into monoamines like tyramine.
Clinical Features
- Rapid onset (within 15-90 minutes of ingestion) of:
- Severe occipital or temporal headache
- Sympathomimetic effects: hypertension, diaphoresis, mydriasis, palpitations, chest pain
- Syndrome usually resolves on own over 6 hours
Differential Diagnosis
Hypertension
- Asymptomatic hypertension
- Hypertensive urgency
- Hypertensive emergency
- Preeclampsia/Eclampsia
- Autonomic dysreflexia
- Drug use or overdose (e.g stimulants or Synthroid)
- Tyramine reaction
- Pheochromocytoma
- Hyperthyroidism
- Anxiety
Evaluation
- ECG: monitor for cardiac ischemia
- CT head: if patient has focal neurologic findings or persistent, severe headache
Management
- Hypertensive emergency: phentolamine is agent of choice
- 2.5-5mg IV q5-15min until blood pressure controlled
- Duration of action <1 hour
- Beta-blockers contraindicated
Disposition
- Discharge home if asymptomatic after 4 hours of observation
