Monoamine oxidase inhibitor toxicity - Revision history

Danbot: Add MedicationDose entries for phentolamine, nitroprusside

2026-03-20T21:04:23Z

Add MedicationDose entries for phentolamine, nitroprusside

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 ==Prevention==
 *Do ''not'' prescribe the following medications if a patient is taking a MAOI: [[meperidine]], [[dextromethorphan]], [[tramadol]], propoxyphene, or [[cyclobenzaprine]]
 ==Disposition==

Rossdonaldson1: /* Differential Diagnosis */

2020-11-14T13:45:26Z

Differential Diagnosis

← Older revision		Revision as of 13:45, 14 November 2020
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	**[[Tyramine Reaction]]		**[[Tyramine Reaction]]
	**[[Neuroleptic Malignant Syndrome (NMS)]]		**[[Neuroleptic Malignant Syndrome (NMS)]]

			{{Movement disorder DDX}}

	==Evaluation==		==Evaluation==

ClaireLewis: /* Differential Diagnosis */

2019-09-01T14:12:26Z

Differential Diagnosis

← Older revision		Revision as of 14:12, 1 September 2019
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	*Intoxications		*Intoxications
	**[[Amphetamines]]		**[[Amphetamines]]
	**[[Antimuscarinics]]		**[[Anticholinergic toxicity\|Antimuscarinics]]
	**Methylxanthine toxicity ([[theophylline toxicity\|theophylline]], [[caffeine toxicity\|caffeine]])		**Methylxanthine toxicity ([[theophylline toxicity\|theophylline]], [[caffeine toxicity\|caffeine]])
	**St. John's Wort		**St. John's Wort

ClaireLewis at 14:11, 1 September 2019

2019-09-01T14:11:36Z

← Older revision		Revision as of 14:11, 1 September 2019
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	==Background==		==Background==
	*MonoAmine Oxidase Inhibitors (MAOI)		*MonoAmine Oxidase Inhibitors (MAOI)
	*Used to treat depression and Parkinsonism (~~e.g. selegiline~~ -> MAO-B at lower doses, MAO-A at higher doses)		*Used to treat depression and Parkinsonism
			*MAOI drugs available in the US include:
			**Isocarboxazid, phenelzine (Nardil), tranylcypromine (Parnate)
			**Selegiline (Deprenyl, Eldepryl, Emsam, Zelapar)--> MAO-B at lower doses, MAO-A at higher doses, rasagiline (Azilect), safinamide (Xadago)
			**[[Linezolid]] is a reversible inhibitor of MAO and produces significant inhibition of MAO-A
			**[[Methylene blue]]<ref>Petzer A, Harvey BH, Wegener G, Petzer JP (February 2012). "Azure B, a metabolite of methylene blue, is a high-potency, reversible inhibitor of monoamine oxidase". Toxicology and Applied Pharmacology. 258 (3): 403–9. </ref>
	*Lead to increased norepinephrine, serotonin, dopamine, tyramine		*Lead to increased norepinephrine, serotonin, dopamine, tyramine
	*Linezolid is a reversible inhibitor of MAO and produces significant inhibition of MAO-A

	===Toxicity Mechanisms===		===Toxicity Mechanisms===
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	==Clinical Features==		==Clinical Features==
	*Similar to hyperadrenergic state (tachycardia, hypertension, hyperthermia)		*Similar to hyperadrenergic state ([[tachycardia]], [[hypertension]], [[hyperthermia]])
	*Severe toxicity accompanied by [[coma]], [[seizure]], [[bradycardia]], [[hypotension]], worsening [[hyperthermia]], [[rhabdomyolysis]]		*Severe toxicity accompanied by [[coma]], [[seizure]], [[bradycardia]], [[hypotension]], worsening [[hyperthermia]], [[rhabdomyolysis]]

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	**[[Amphetamines]]		**[[Amphetamines]]
	**[[Antimuscarinics]]		**[[Antimuscarinics]]
	**Methylxanthine toxicity (theophylline, caffeine)		**Methylxanthine toxicity ([[theophylline toxicity\|theophylline]], [[caffeine toxicity\|caffeine]])
	**St. John's Wort		**St. John's Wort
	*Withdrawal states		*Withdrawal states
	**[[Ethanol withdrawal\|Ethanol]]		**[[Ethanol withdrawal\|Ethanol]]
	**[[Benzodiazepine withdrawal]]		**[[Benzodiazepine withdrawal]]
	**Clonidine		**[[Clonidine]]
	**Beta-blockers		**[[Beta-blockers]]
	*Medical conditions		*Medical conditions
	**[[Heat stroke]]		**[[Heat stroke]]
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	==Evaluation==		==Evaluation==
	*~~asymptomatic~~ period followed by delayed toxicity can suggest MAO-I toxicity		*Asymptomatic period followed by delayed toxicity can suggest MAO-I toxicity
	*urine immunoassays and mass spectroscopy can fail to detect MAOI (patients taking selegiline will test positive for ~~metamphetamine~~)		*urine immunoassays and mass spectroscopy can fail to detect MAOI (patients taking selegiline will test positive for methamphetamine)
	*consider ECG and chemistry panel in MAOI overdose patients who are obtunded		*consider ECG and chemistry panel in MAOI overdose patients who are obtunded

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	#Supportive care		#Supportive care
	#*Hypertension		#*Hypertension
	#**Treat only with short-acting agents: may develop precipitous hypotension		#**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		#**[[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		#**[[Nitroprusside]]: 1mcg/kg/min and titrate up
	#*Hypotension: intravenous fluid +/- norepinephrine		#*Hypotension: intravenous fluid +/- [[norepinephrine]]
	#*CNS excitation and [[Seizures]]: benzodiazepines are 1st line		#*CNS excitation and [[Seizures]]: [[benzodiazepines]] are 1st line
	#*Hyperthermia		#*Hyperthermia
	#**Routine cooling measures		#**Routine cooling measures
	#**Consider paralysis if patient has persistent muscle rigidity		#**Consider paralysis if patient has persistent muscle rigidity


			==Prevention==
			*Do ''not'' prescribe the following medications if a patient is taking a MAOI: [[meperidine]], [[dextromethorphan]], [[tramadol]], propoxyphene, or [[cyclobenzaprine]]

	==Disposition==		==Disposition==
	*Admit all patients for 24 hour observation to monitored setting (risk of delayed hyperadrenergic symptoms)		*Admit all patients for 24 hour observation to monitored setting (risk of delayed hyperadrenergic symptoms)

	~~==Prevention==~~
	*Do not prescribe the following medications if a patient is taking a MAOI: meperidine, dextromethorphan, tramadol, propoxyphene, or cyclobenzaprine

	==See Also==		==See Also==

Beren85: /* Background */

2019-09-01T13:42:38Z

Background

← Older revision		Revision as of 13:42, 1 September 2019
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	==Background==		==Background==
	*MonoAmine Oxidase Inhibitors (MAOI)		*MonoAmine Oxidase Inhibitors (MAOI)
	*Used to treat depression and Parkinsonism (e.g. selegiline)		*Used to treat depression and Parkinsonism (e.g. selegiline -> MAO-B at lower doses, MAO-A at higher doses)
	*Lead to increased norepinephrine, serotonin, dopamine, tyramine		*Lead to increased norepinephrine, serotonin, dopamine, tyramine
	*Linezolid is a reversible inhibitor of MAO and produces significant inhibition of MAO-A		*Linezolid is a reversible inhibitor of MAO and produces significant inhibition of MAO-A

Beren85: /* Management */

2019-09-01T13:41:43Z

Management

← Older revision		Revision as of 13:41, 1 September 2019
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	#**[[Nitroprusside]]: 1mcg/kg/min and titrate up		#**[[Nitroprusside]]: 1mcg/kg/min and titrate up
	#*Hypotension: intravenous fluid +/- norepinephrine		#*Hypotension: intravenous fluid +/- norepinephrine
	#*[[Seizures]]: benzodiazepines are 1st line		#*CNS excitation and [[Seizures]]: benzodiazepines are 1st line
	#*Hyperthermia		#*Hyperthermia
	#**Routine cooling measures		#**Routine cooling measures

Beren85: /* Disposition */

2019-09-01T13:39:03Z

Disposition

← Older revision		Revision as of 13:39, 1 September 2019
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	==Disposition==		==Disposition==
	*Admit all patients for 24 hour observation to monitored setting		*Admit all patients for 24 hour observation to monitored setting (risk of delayed hyperadrenergic symptoms)

	==Prevention==		==Prevention==

Beren85: /* Evaluation */

2019-09-01T13:35:45Z

Evaluation

← Older revision		Revision as of 13:35, 1 September 2019
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	==Evaluation==		==Evaluation==
	*asymptomatic period followed by delayed toxicity can suggest MAO-I toxicity		*asymptomatic period followed by delayed toxicity can suggest MAO-I toxicity
	*urine immunoassays and mass spectroscopy can fail to detect MAOI		*urine immunoassays and mass spectroscopy can fail to detect MAOI (patients taking selegiline will test positive for metamphetamine)
	*consider ECG and chemistry panel in MAOI overdose patients who are obtunded		*consider ECG and chemistry panel in MAOI overdose patients who are obtunded

Beren85: /* Differential Diagnosis */

2019-09-01T13:33:22Z

Differential Diagnosis

← Older revision		Revision as of 13:33, 1 September 2019
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	**[[Amphetamines]]		**[[Amphetamines]]
	**[[Antimuscarinics]]		**[[Antimuscarinics]]
			**Methylxanthine toxicity (theophylline, caffeine)
	**St. John's Wort		**St. John's Wort
	*Withdrawal states		*Withdrawal states
	**[[Ethanol withdrawal\|Ethanol]]		**[[Ethanol withdrawal\|Ethanol]]
			**[[Benzodiazepine withdrawal]]
	**Clonidine		**Clonidine
	**Beta-blockers		**Beta-blockers
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	**[[Hypoglycemia]]		**[[Hypoglycemia]]
	**[[Hyperthyroidism]]		**[[Hyperthyroidism]]
			**[[Meningitis]]
			**[[Encephalitis]]
			**[[Pheochromocytoma]]
			**[[Carcinoid syndrome]]
	*Adverse drug reactions		*Adverse drug reactions
	**[[Malignant Hyperthermia]]		**[[Malignant Hyperthermia]]

Beren85: /* Clinical Features */

2019-09-01T13:29:55Z

Clinical Features

← Older revision		Revision as of 13:29, 1 September 2019
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	==Clinical Features==		==Clinical Features==
	*Similar to hyperadrenergic state		*Similar to hyperadrenergic state (tachycardia, hypertension, hyperthermia)
	*Severe toxicity accompanied by [[coma]], [[seizure]], [[bradycardia]], [[hypotension]], worsening [[hyperthermia]]		*Severe toxicity accompanied by [[coma]], [[seizure]], [[bradycardia]], [[hypotension]], worsening [[hyperthermia]], [[rhabdomyolysis]]

	==Differential Diagnosis==		==Differential Diagnosis==