Monoamine Oxidase Inhibitor Poisoning
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Basics
Description
- Primarily for depression
- Selegiline, a selective monoamine oxidase B inhibitor, is sometimes used to treat Parkinson disease, and also comes in a transdermal preparation
- Monoamine oxidase inhibitor (MAOI) pharmacologic actions:
- Disruption of equilibrium between endogenous monoamine synthesis and degradation, resulting in:
- Increased neural norepinephrine levels
- Downregulation of several receptor types
- Inhibition of irreversible (noncompetitive) enzyme
- Inhibition of other B6-containing enzymes
- Disruption of equilibrium between endogenous monoamine synthesis and degradation, resulting in:
- MAO: Principal inactivator of neural bioactive amines:
- MAO A:
- Present in the gut and liver
- Protects against dietary bioactive amines
- MAO B:
- Present in neuron terminals and platelets
- Sympathomimetic amines: Types of bioactive amines
- MAO A:
Etiology
- MAOI overdose:
- Toxicopharmacology poorly understood
- MAO inhibitors: Amphetamine-like in structure:
- Early: Indirect sympathomimetic effect
- Late: Sympatholytic response (hypotension)
- MAOI hypertensive crisis syndrome:
- Results from impaired norepinephrine degradation and large norepinephrine release precipitated by an indirect- or mixed-acting sympathomimetic agent
- Common precipitants: Tyramine, cocaine, amphetamines
- Serotonin syndrome (SS):
- Commonly results from exposure to combinations of agents that affect serotonin metabolism or action
- Increases serotonin synthesis: Tryptophan
- Increase serotonin release:
- Indirect- and mixed-acting sympathomimetic agents and dopamine receptor agonists
- Decrease serotonin reuptake:
- Selective serotonin reuptake inhibitors
- Tricyclic antidepressants
- Newer antidepressants: Trazodone, nefazodone, venlafaxine
- Phenylpiperidine opioids: Meperidine, dextromethorphan, tramadol, methadone, propoxyphene
- Direct serotonin receptor agonists:
- Buspirone, sumatriptan, lysergic acid diethylamide
- Decrease serotonin breakdown:
- MAOIs
- Increases nonspecific serotonin activity:
- Lithium
-- To view the remaining sections of this topic, please log in or purchase a subscription --
Basics
Description
- Primarily for depression
- Selegiline, a selective monoamine oxidase B inhibitor, is sometimes used to treat Parkinson disease, and also comes in a transdermal preparation
- Monoamine oxidase inhibitor (MAOI) pharmacologic actions:
- Disruption of equilibrium between endogenous monoamine synthesis and degradation, resulting in:
- Increased neural norepinephrine levels
- Downregulation of several receptor types
- Inhibition of irreversible (noncompetitive) enzyme
- Inhibition of other B6-containing enzymes
- Disruption of equilibrium between endogenous monoamine synthesis and degradation, resulting in:
- MAO: Principal inactivator of neural bioactive amines:
- MAO A:
- Present in the gut and liver
- Protects against dietary bioactive amines
- MAO B:
- Present in neuron terminals and platelets
- Sympathomimetic amines: Types of bioactive amines
- MAO A:
Etiology
- MAOI overdose:
- Toxicopharmacology poorly understood
- MAO inhibitors: Amphetamine-like in structure:
- Early: Indirect sympathomimetic effect
- Late: Sympatholytic response (hypotension)
- MAOI hypertensive crisis syndrome:
- Results from impaired norepinephrine degradation and large norepinephrine release precipitated by an indirect- or mixed-acting sympathomimetic agent
- Common precipitants: Tyramine, cocaine, amphetamines
- Serotonin syndrome (SS):
- Commonly results from exposure to combinations of agents that affect serotonin metabolism or action
- Increases serotonin synthesis: Tryptophan
- Increase serotonin release:
- Indirect- and mixed-acting sympathomimetic agents and dopamine receptor agonists
- Decrease serotonin reuptake:
- Selective serotonin reuptake inhibitors
- Tricyclic antidepressants
- Newer antidepressants: Trazodone, nefazodone, venlafaxine
- Phenylpiperidine opioids: Meperidine, dextromethorphan, tramadol, methadone, propoxyphene
- Direct serotonin receptor agonists:
- Buspirone, sumatriptan, lysergic acid diethylamide
- Decrease serotonin breakdown:
- MAOIs
- Increases nonspecific serotonin activity:
- Lithium
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