Overdose/TCA toxicity Flashcards
History questions to ask in a suspected overdose
what drugs were taken
how many pills
when was the OD taken
why was it taken
**ask for an empty bottle of available
any known or witnessed trauma details
PMHx or social history to ask in a suspected overdose
drug allergies
medical conditions–> DM, known seizure activity
prescription meds
concurrent ingestion of alcohol or recreational drugs
any previous attempts
previous depression or psychiatric history
how should you approach a patient with suspected overdose with a depressed level of consciousness
should be initially managed in a similar fashion
should always include particular attention to ABCs and necessary management done simultaneously with the initial exam to ensure secondary complications of ingestion are prevented
vitals with the inclusion of O2 sats and EKG monitoring–> watch for arrhythmias
when time permits, then do a full secondary assessment
what types of secondary complication from suspected overdose do you try and prevent during primary survey/treatment in a patient with depressed consciousness
hypoxia aspiration respiratory failure cardiac arrest shock
what initial investigations should be done in suspected overdose
CBC lytes BUN Cr, eGFR serum glucose baseline LFTs ABGs serum osmolality blood screening for specific agents ECG chest xray consider CT head if trauma urine pregnancy test
what specific agents should be screened for in suspected overdose
ASA acetaminophen alcohol toxic alcohols digoxin barbiturates benzodiazepines amphetamines cocaine TCAs
what is the “coma cocktail”
if ingestion is unknown
involves administration of
naloxone 2 mg IV
thiamine 100 mg IV
50 cc of 50% dextrose
flumazenil is generally not included in this initial treatment unless there is a high suspicion of benzodiazepine or ethylene glycol overdose
describe a general approach to overdose management
ABCs oxygen IV access monitor vitals, with cardiac monitoring
administer coma cocktail if ingestion unknown
in what situation would you give flumazenil
suspected or confirmed benzodiazepine or ethylene glycol overdose
why do you avoid giving flumanzenil unless confidently indicated
because it makes seizure control difficult by rendering your primary anti-seizure meds, benzos, ineffective
what is the role of syrup of ipecac in the ER with suspected overdose
not usually useful in the emergency setting as the induction of vomiting may delay subsequent therapy–its use has fallen out of favour
what is the role of gastric lavage in the ER with suspected overdose
can be useful if initiated within 60-90 minutes of the ingestion
the airway however must be protected in patients with decreased or absent gag reflex
use 28-36 F (larger the better) with 200-300mL boluses of warm saline until the effluent is clear
what is the role of activated charcoal in the ER with suspected overdose
no controls trials demonstrating harm after using it
may be useful in almost ALL overdoses if given less than 2 hours after toxic ingestion
should NOT be used in patients with decreased LOC without proper airway management
first dose should be given as 50g diluted in sorbitol and the following doses should be in water, every hour
who should you not use activated charcoal in
should NOT be used in patients with decreased LOC without proper airway management
how do you administer activated charcoal
first dose should be given as 50g diluted in sorbitol and the following doses should be in water, every hour
in what situations related to suspected overdose should you consider peritoneal or hemodialysis
useful for low molecular weight, water soluble toxins that are minimally bound to plasma proteins
these include ethanol ethylene glycol methanol lithium salicylates
consider if
clinical deteriorate despite intensive therapy
blood toxin levels reach potentially lethal concentrations
renal or hepatic failure impairs clearance of toxins
list 4 common classes of drugs you may often see in an OD situation
salicylates
opiates
anticholinergic
cholinergic
symptoms of salicylate overdose
hyperthermia
tachycardia
tinnitus
respiratory alkalosis
AG metabolic acidosis or mixed A/B disturbance
specific treatment for salicylate OD
supportive
glucose
charcoal
alkalinization
symptoms of opiate overdose
CNS depression
respiratory depression
miosis (pinpoint)
hypotension
specific treatment for opiate OD
maloxone 0.4-2mg IV and repeat PRN
what types of common drugs are anticholinergic
TCA
antihistamines
atropine
gravol
specific symptoms of anticholinergic overdose
dry as a bone mad as a hatter blind as a bat hot as hades red as a beet and the heart runs alone \+ grabbing invisible objects and shaking
dry skin, mouth, urinary retention confused blurred vision/mydriasis (big pupils) hyperthermia flushed skin tachycardia
specific treatment for TCA overdose
NAHCO3 1-2mmol/kg IV if having an arrhythmia
specific treatment for anticholinergic overdose
lorazepam 2-3 mg IV q5 minutes
physostigmine
what types of drugs would result in a cholinergic overdose
acetylcholine
organophosphates
wild mushrooms
symptoms of a cholinergic overdose
hypersalivation bronchorrhea bronchospasm urination/defecation lacrimation neuromuscular failure
treatment of cholinergic overdose
atropine 2 mg IV repeat q 5-30 minutes
name the TCAs
amitriptyline imipramine desipramine nortriptyline doxepine
what are the leading cause of drug OD in the USA
TCAs
what amount of TCA leads to overdose
greater than 20 mg/kg with 35mg/kg being the approximate median lethal dose
what are the pharmacologic actions of TCAs that must be specifically addressed in TCA overdose
peripheral anticholinergic activity
myocardial depression
respiratory depression
slowing of atrioventricular conduction
how do you treat TCA overdose and why is that used
alkalinization with IV sodium bicarbonate
sodium bicarbonate 1-2mEq/kg to maintain arterial pH of 7.45 to 7.55
this is done to prevent and treat hypotension, arrhythmias and conduction disturbances
what arterial pH is targeted in the treatment of TCA overdose
7.45-7.55
which patients with TCA overdose should be transferred to the ICU
respiratory depression
hypotension
cardiac arrhythmias
how should you manage someone with a suspected TCA overdose who is asymptomatic
if have a NORMAL EKG, they can be observed in the emergency room with cardiac monitoring for 6 hours following ingestion, decontamination and REPEATED CHARCOAL
once medically stable, they should be evaluated by psychiatry
what arrhythmia is associated with TCA overdose
*QRS duration above 100ms and rightward axis
prolonged PR, QRS and QT intervals (wide complex arrhythmia)
AV block
non specific ST segment and T wave changes
right axis deviation
Brugada pattern
- sinus tachy is the most common abnormality due to anticholinergic activity and inhibition of norepinephrine uptake by TCAs
- torsades occurs uncommonly
what is the Brugada ECG pattern
downsloping ST segment elevation in leads V1-V3 in association with RBBB
in what time period would you expect death to occur from TCA poisoning
life threatening arrhythmias and death due to TCA poisoning usually occurs within 24 hours of ingestion
rapid deterioration is common
what is the most sensitive clinical predictor of serious complications in TCA poisoning
LOC at presentation
