Monoamine oxidase inhibitor toxicity: Difference between revisions
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Revision as of 14:58, 4 December 2016
Background
- Mono Amine Oxidase Inhibitors (MAOI)
- Used to treat depression and Parkinsonism (e.g. selegiline)
- Lead to increased norepinephrine, serotonin, dopamine, tyramine
- Toxicity often delayed 6-24 hours after ingestion
Clinical Features
- Similar to hyperadrenergic state
- Severe toxicity accompanied by coma, seizure, bradycardia, hypotension, worsening hyperthermia
Differential Diagnosis
- Intoxications
- Withdrawal states
- Ethanol
- Clonidine
- Beta-blockers
- Medical conditions
- Adverse drug reactions
Evaluation
- asymptomatic period followed by delayed toxicity can suggest MAO-I toxicity
- urine immunoassays and mass spectroscopy can fail to detect MAOI
- consider ECG and chemistry panel in MAOI overdose patients who are obtunded
Management
- Gastric decontamination
- Lavage indicated if can be performed <1 hour after ingestion
- Activated charcoal x 1
- Supportive care
- Hypertension
- Treat only with short-acting agents: may develop precipitous hypotension
- Phentolamine: 2.5-5mg IV bolus q15-15min; can also give as infusion 0.2-0.5mg/min
- Nitroprusside: 1mcg/kg/min and titrate up
- Hypotension: intravenous fluid +/- norepinephrine
- Seizures: benzodiazepines are 1st line
- Hyperthermia
- Routine cooling measures
- Consider paralysis if patient has persistent muscle rigidity
- Hypertension
Disposition
- Admit all patients for 24 hour observation to monitored setting
Prevention
- Do not prescribe the following medications if a patient is taking a MAOI: meperidine, dextromethorphan, tramadol, propoxyphene, or cyclobenzaprine
See Also
References
- Rosen's