Antidepressants Flashcards
mechanism of MAO A inhibitor toxicity
decreased amine degradation
amphetamine like effect and increaased catecholamine release
decreased amine reuptake
increased amine release
4 phases of MAOi overdose
- asymptomatic period up to 6-12 hr (monitor for 24hr post ingestion)
- neuromuscular excitation and symptathetic hyperactivity: HTN, tremor, seizure, rigid, agitation, hyperthermia, diaphoresis, myoclonus
- CNS depression and possible CV collapse - hypotension
- secondary complications for survivors
hypertension treatment in MAOi overdose
short actign agent for severe hypertension bc will go hypotensive after
hypotension use direct acting vasopressors
rigidity treatment in MAOi overdose
benzo
dantrolene
to prevent rhabdomyolysis bc severe muscle tension breaks down the muscles and gets stuck in kidneys
charcoal effective in MAOi overdose
yes
cause of eating indirect acting amines (cheese, fish) when on MAOi
peripheral hypertensive crisis
anticholinergic effects of tcas
agitation hallucination confusion sedation coma seizure hypertension tachycardia hyperthermia mydriasis dry flushing skin decreased GI motility urinary retention
TCA toxic effect - cardiovascular
QRS prolongation
sinus tachycardia
ventricular arrhythmias
hypotension
TCA toxic effect - CNS
coma
delerium
myoclonus
seizures
hyperthermia
ileus - lack of movement in intestines
urinary retention
risk factors increasing risk of toxicity in TCAs
pre existing heart conditions electrolyte abnormalities hepatic insufficiency stimulant drug use multiple drugs that increase QT intervals increased dose
general management of TCA overdose
airway IV line cardiac monitoring - EKG stomach lavage charcoal 50-100g + cathartic decreased LOC - oxygen, dextrose, naloxone, thiamine, ABG
toxic dose of tca
10-20mg/kg
limit rx to 1g
most common cause of death in tca overdose
refractory hypotension due to vasodilation or impaired cardiac contractility
treatment of orthostatic hypotension tca
intravascular volume expansion
sodium bicarb, vasopressors, or inotropes
correct hyperthermai, acidosis, seizures
treatment of cns effects in tca overdose
supportive
benzos
midazolam infusion for seizure, refractory barbiturates or propofol
not phenytoin due to arrhythmias
tca cardiac cause of death
myocardial depression
ventricular tachycardia
ventricular fibrillation
why do we do EKG in tca overdose
qrs duration >.10sec predictor of arrhythmias
serum concentrations not predictive
treatment of cardiac toxicity in tca overdose
sodium bicarb narrows QRS reducing arrhythmias and hypotension
antiarrhythmics are contraindicated
when is lipid rescue used
refractory cardiotoxicity for overdoses of lipophuilic meds (TCA, local anesthetic poisoning)
last ditch effort
MOA of lipid rescue
lipid sink
drug stays in blood stream doesnt go to receptors
length of tx in asymptomatic tca overdose
good once normal ECG x 6 hr with treatment GI decontamination
length of treatment if symptomatic with altered mental status, seizue, cardiac dysrrhythmia
monitor in ICU 12-24hr after all symptoms resolved and all supportive interventions are discontinued
if all parameters norma then psychiatry to evaluate
toxicity of antidepressants
- amitriptyline
- venlafaxine
- mirtazapine
- citalopram
venlafaxine overdose
proarrhythmic seizure hypertension? sinus tachycardia serotonin syndrome blood pressure increased
venlafaxine contraindicated in
high risk overdoses
pre existing seizures and cardaic disease
poor CYP2D6 metabolizers or drugs that inhibit this
treatment of venlafaxine overdose
treat similar to TCA overdose
have to monitor for longer just in case a poor metabolizer
venlafaxine metabolite
desvenlafaxine
toxicity seems low
toxicity signs and symptoms of duloxetine
somnolence serotonin syndrome seizure vomiting QRS prolong and arrythmia low mostly neurologic and GI effects
SSRI toxic effects
tremor sinus tachycardia NV diarrhea obtundation seizure serotonin syndrome
treatment of SSRI toxicity
charcoal
supportive care
tx of serotonin syndrome
supportive care
neuromuscular - benzo
increased temp - tylenol
rigidity - dantrolene
tx of severe symptoms in serotonin syndrome
cyproheptadine 4mg q4hr
serotonin antagonism
watch anticholinergic and antihistaminic properties
signs and symptoms or serotonin syndrome
agitation confusion diaphoressi diarrhea fver shivering myoclonus tremor incoordination hyperreflexia
citalopram only SSRI with cardiac toxicity what are the issues
dose related QT prolongation
increased risk of torsades de pointes
bupropion safety
not a lot of cardiac issues seizures GI upset tahycardia agitation hypertension
problems with XL bupropion
half life prolonged delayed transit time so more can be absorbed
DELAYED HIGHER PEAK
delayed onset seizures
mirtazapine safety
tachycardia
hypertension
no cardiac issues or seizures
watch for serotonergic and anticholinergic effects
