Lecture 3 - Management of Acute Toxicologic Emergencies Flashcards
PK factors to consider when evaluating potential drug OD?
- Drug susceptible to Bezoar formation?
- Was a time-release/SR formulation ingested?
- Does drug have anticholinergic properties that may reduce gastric emptying
- If pt Hypotensive (SBP <90), see dec absorption, clearance, metabolism maybe
- Is drug metabolism saturable
Sources of False positive results for Amphetamines
Pseudoephedrine
Phenylephrine
Trazadone
Raniditine
Sources of False positive results for Benzo
Sertraline
Sources of False positive results cannabinoid
Ibuprofen
Naproxen
Sources of False positive results coke metabolite
“caine” anesthetics
Sources of False positive results Opioids
Rifampin
Fluoroquinolone antibiotics
Synthetic opioids may not be detected
If inhaled poison then…
get person to fresh air ASAP, start artificial respiration prn
If poison on skin…
remove contained clothing, Flood skin with water, wash with soap
if poison in the eye…
flush the open eye with room temp water for 10-15min, remove contacts
If swallowed poison….
give 2-4oz of water, seek further help
Using Ipecac syrup in OD?
no role in ANY OD situation
Approach to poisoning in Hospital?
Support airway
Manage seizures, arrthymias, electrolytes, etc
Gastric lavage = only if ingestion within last hr**
Activated Charcoal
- Highly absorbent that binds many toxins
- no effective w/ Lithium and iron
- given up to 6hrs after ingestion, best within 1hr
- use Sorbitol w/ 1st dose only
- don’t give at home
1-12 = 25-50g Adults = 25-100g
Whole bowel irrigation
- using a PEG solution
- Large volume admin over 12hrs to clear GI
- Few risks, but little evidence suggesting benefit
When to use Whole-Bowel irrigation
- ingestion several hrs prior to hospital presentation
- Ingestion of SR or enteric coated formulations
- substances like iron that dont absorb to charcoal
Acetaminophen antidote
Acetylcysteine
Anticholinergic antidote
Physostigmine
Warfarin antidote
Phytonadione
Benzo antidote
Flumazenil = short duration tho
Digoxin antidote
Digoxin immune fab
Ethylene glycol antidote
Fomepizole
Iron antidote
Deferoxamine
Isoniazid antidote
Pyridoxine
Opioid antidote
Naloxone
Acute Acetaminophen Toxicity (Time 0-24hrs after ingestion)
May sea N,V, diaphoresis but many patients are asymptomatic
Acute Acetaminophen Toxicity (Time 2-3 days after ingestion)
Asymptomatic ise in AST/ALT and bilirubin
Acute Acetaminophen Toxicity (Time 3-5 days after ingestion)
Signs + symptoms of hepatic injury
- Jaundice, RUQ tenderness, hypoglycemia,encephalopathy, elevated INR
- hepatic failure may progress to hepatic coma and death
Mechanism of Acetaminophen toxicity
w/ OD, sulfate stores are rapidly depleted and inc acetaminophen is metabolized through CYP 450
~ 90% cleared via glucuronidation but its saturated in OD
~5% CYP450 metabolized but produces active metabolite NAPQI which is bad, it depletes glutathiones
Increased NAPQI = hepatotoxicity
can also see acute renal failure
Factors to influence risk for Hepatotoxicity w/ Acetaminophen
Inc risk in adults, dec risk in kids
Pts frequently dont know they’re taking excessive acetaminophen
pts with induced CYP2E1 (alcoholic) = inc risk
inc risk w/ dose > 10g, repeated high doses 2-6g over 24hrs, or 6g/day for 5+ days.
Treat pt with NAC if….
Line on Nomogram is above the Nomogram treatment line
Usually stay on side of caution and start NAC
Always start NAC if….
time of ingestion is unknown or 8 hrs have elapsed since acute ingestion and serum acetaminophen lvl is not back
if start, always finish full course of NAC
IV NAC dosing
Given over 21 hrs
$$$$
Oral NAC dosing
Given over 72 hrs
tastes bad
$
CCB OD results from….
1g of Diltiazem, nifedipine or verapamil = severe symptoms
acute or chronic poisoning = symptoms w/ lower doses
Possible Symptoms of CCB OD
Hypotension
Bradycardia = none with nifedipine or amlodipine*****
Hyperglycemia
Symptoms usually within 1-2hrs of ingestion, delayed effect is CD or SR product
CCB OD treatment to stabilize pt
Give charcoal within 2hrs of ingestion
Intubate
Aggressive IV fluid resuscitation and place pt in reverse Trendelenberg position
Dopamine infusion if SBP < 90
Atropine 1mg IVP q5min X 2 if HR < 50
How long within ingestion can you give Charcoal for Acetaminophen OD?
Within 4hrs
CCB OD treatment after pt is stabilized
Intralipid 20% 100ml IVP X 1, then 100ml/hr weaning off as signs of toxicity resolve
Start regardless of HR/BP
2 potential mechanism for Intralipid
- binds to lipid drugs like CCB = Lipid sink phenomenon
2. rapid energy source to cardiac cells, increasing contractility
If pt will has dec HR or BP after intralipid then give…
- IV calcium Cl (IVP -> infusion)= IVP is test dose, if HR or SBP dont inc by > 10% then move on to regular insulin
- Regular insulin (IVP-> Infusion) = if inadequate response < 10%, move to glucagon…HR < 50, SBP < 90
- Glucagon (IVP -> Infusion)
TCA OD symptoms
Neurologic = lethargy, coma, seizures
CV = Tachycardia, Prolonged QRS interval ( > 160msec = predictive of severe effects), Hypotension
TCA OD treatment
- Activated Charcoal 50g PO X 1…can repeat
- Sodium bicarb 50mEq IVP X 1 Q30min IF QRS interval > 160msec, SBP < 90 or Vtach
- Lidocaine 1g IVP X 1 IF Vtach…dont use procainamide or amiodarone as it can worsen QRS prolongation
Who is at risk for Acute Opioid Toxicity
- Anyone using/abusing opioid drugs
- pts on high dose for pain management
- elderly
- IV drug abuse
- Users recently out of Detox
- Mixing with bento + booze
- Comorbid conditions
- Potency of street opioids
Acute opioid poisoning
Respiratory depression
Sedation
Pinpoint pupils
Absence of bowl sounds
Seizures w/ meperidine or tramadol
Muscle rigidity w/ Fentanyl
Mechanism of Naloxone
Knocks of opioids from Mu receptors
Opioid OD treatment
IVP dose: 0.5,2,4,8,16mg.
start with 0.5, if RR < 10min after 2 min and continue until RR > 10.
If methadone or SR opioid…start IV infusion of naloxone at hrs dose that is 50% of last effective bolus dose
rare side effects of naloxone?
Poop
Agitation
1/2life shorter than most opioids so symptoms of OD can return
