Toxicology Lecture Flashcards
MC antidepressants to cause OD related deaths
Tricyclic antidepressants
Altered mental status
Sinus tachycardia
serious toxicity seen within 6 hours:
coma, cardiac conduction delays, supraventricular tachycardia, hypotension, respiratory depression, premature ventricular beats, v tach, seizures
Tricyclic OD
R axis deviation
Terminal R wave in aVR
Widened QRS
ECG changes seen within ____ hours of a tricyclic OD
6 hours!
Shock
Prolonged QRS
Terminal R waves in aVR
Altered mental status
Tricyclic OD
MC tricyclic that is taken for OD
amitriptyline
Peak absorption is 1 hour
Toxic dose= 10-20 mg/kg
Tricyclic OD
O2, IV, monitor
BICARB!! 1-2 mEq/kg until blood pH equals 7.50-7.55
intubate if necessary
Tx for tricyclic OD
sx: agitation, confusion, tremor, rigidity, sweating, hyper-reflexia, anxiety, ataxia
ie. .a pt took a whole bottle of their SSRIs
Serotonin syndrome
SSRIs cause ____ symptoms
psych!
(hyperreflexia, rigidity, agitation)
Due to hyper-reflexia, rigidity, myoclonus etc…pts who OD on SSRIs (serotonin syndrome) can give themselves…
Rhabdo
Tx for serotonin syndrome?
Benzos
__-___% of patients on long term lithium therapy will develop toxicity
75-90%
Hand tremor, polyuria, rash
Nephrogenic diabetes insipidus
Neuro effects: memory loss, decreased mental status, fatigue, ataxia, dysarthria
N/V/D
Hypotension, conduction delays, ventricular dysrhythmias
QT prolongation, ST segment depression, T wave inversion
Lithium OD
very narrow therapuetic index, make sure these pts stay hydrated!
0-12 hours: CNS effects
pt appears intoxicated without smell of ethanol on breath
12-24 hrs: cardiopulmonary effects
tachycardia, tachypnea, HTN
CHF, ARDS, circulatory collapse
24-72 hours: renal effects
flank pain, CVA tenderness, acute tubular necrosis with acute renal failure
Ethylene glycol OD
Metabolic acidosis with elevated anion gap and elevated osmolal gap
Ethylene glycol OD
Serum osmolal= 10
Calculated osmolal= 3.8
..what are you missing?
Ethylene glycol OD!
conversion factor for Ethylene Glycol= 6.2, which is the difference between the serum and calculated levels
Ethylene glycol= 6.2
Methanol= 3.2
Ethanol= 4.6
conversion factors
Fomepizole=DOC!
Also give bicarb to correct acidosis
end game=dialysis!!
(but this is expensive, so cheap alcohol will also work)
Treatment for ethylene glycol OD
What is MUDPILES?
causes of elevated anion gap
- *M**ethanol
- *U**remia
- *D**KA
- *P**ropylene glycol
- *I**nfection/isonizid
- *L**actic acidosis
- *E**thylene glycol/ethanol
- *S**alicylates
Na- (Bicarb + Cl)
Anion gap
normal= 12 or under
What is a normal anion gap?
12 or under
Kussmal’s breathing (hyperventilation)
Tinnitis
Aspirin OD!
If a pt has kussmal’s respirations, you can pretty much assume they are in what?
Metabolic acidosis
(body is trying to blow off CO2 to compensate)
less than 150 mg/kg ingestion of aspirin
non toxic to mild
150-300 mg/kg of aspirin
mild to moderate toxicity
300-500 mg/kg of aspirin
serious toxicity!
>500 mg/kg of aspirin
Potentially life threatening
For a suspected aspirin OD, you must repeat serum salicylate levels ever 2 hours for __ hours
6 hours
(toxic levels are usually apparent within 6 hours)
increased anion gap metabolic acidosis, metabolic alkalosis and respiratory alkalosis
Aspirin OD
Is the Done monogram useful for Aspirin ODs?
NO
Monitor urine pH and maintain at 7.5-8.0
(alkalize the urine)
Aspirin OD
What is the ultimate treatment of choice for Aspirin OD?
Dialysis
For an Aspirin OD, gastric lavage can be done within the first…
60 mins
What is the max dose for Tylenol in adults?
4 grams
MC cause of acute liver failure in US?
Tylenol
What age group does the best with Tylenol ODs?
Kids under 5
(bc they have more Glutathione in liver, which makes it easier to metabolize Tylenol)
What is the worst possible thing you could do in addition to ODing on Tylenol
Drinking alcohol with it!!
(same enzyme metabolizes both)
phase 1 (0-24 hrs)
asymptomatic to N/V
Subclinical bump in LFTs (this is the first sign!)
Tylenol OD
Phase 2 (18-72 hours)
RUQ pain
N/V
Continued increase in LFTs
Tylenol OD
Phase 3 (72-96 hours)
Jaundiced
Coagulopathy
Fatality
Liver necrosis
Renal failure
Tylenol OD
When is the max absorption in a Tylenol OD?
4 hours
(so get labs right away and repeat at 4 hours)
Plot levels at 4 hours on _______ _______ to determine if hepatic toxicity is likely
Rumack Nomogram
Can you use the Rumack Nomogram if 2+ drugs wee taken or if the pt delays the trip to the ER?
NO
What should the blood pH be in a Tylenol OD?
Normal!
(if pt has acidosis, there must be another agent on board)
N-acetylcysteine (NAC) is the antidote for….
Tylenol OD
What is the time frame you want to give N-Acetylcysteine in?
best if within 8 hours
(but can give anytime, even if pregnant)
pH <7.3
Grade 3+ encephalopathy
PT >100
Serum Cr > 3.4
Liver transplant requirements
True or False..
N-acetly-p-benzoquinoneimine (NAPQI) is the toxic metabolite of Acetaminophen
True
Bradycardia + hypotension
serious ingestion when >1 gram
onset= 15 mins - 2 hours
Verapamil OD
(physiologically, this combination does not make sense)
DOC for CCB (Verapamil) OD?
CaCl 10%
10-20 mg q30 minsx 8 hours
DOC for beta-blocker OD
Glucagon
Time to peak effect of opiates for the following methods:
IV
Crush/snort
IM
Oral
Transdermal
IV= 10 mins Snort= 10-15 mins IM= 30-45 mins Oral= 90 mins Transdermal= 2-4 hours
Pressors and Atropine can be given as support tx (CaCl=DOC!!)
*often see high grade blocks of ECG
Verapamil OD
