Final Exam Toxicology Flashcards
Cholinergic Toxidrome
SLUDGE
Salivation
Lacrimation
Urination
Defecation
Gastrointestinal Symptoms
Emesis
Triple B’s/Killer B’s
Bronchorrhea
Bradycardia
Bronchospasm
Anticholinergic Toxidrome
Sympathetic Toxidrome
Agitation
Anxiety
Bronchodilation
HTN
Mydriasis
Tachycardia
Urinary Retention
Seizures
Toxidrome Comparison
Treatment Strategies
Prevent absorption
Enhance elimination
Block effects
GI Decontamination: Activated Charcoal
Other Methods of GI Decon
Emesis
Not recommended
Gastric Lavage
Scare evidence
Use within 30-60 minutes of ingestion
Cathartics
No indication for routine use
Whole Bowel Irrigation
Large amount of osmotically balanced polyethylene glycol electrolyte lavage solution
Ingestion of toxic amount of drug that is not adsorbed to activated charcoal, ER preparations, or Body packers
When is Activated Charcoal NOT Useful
Caustic/corrosive solution
Heavy metals (iron/lead/mercury)
Alcohols
Rapidly absorbed substances
Cyanide
Organophosphates
Aliphatic hydrocarbons
Lithium
Hemodialysis
Urinary Alkalization
Opioids
Causative agents: Buprenorphine, Codeine, Fentanyl, Heroin, Hydrocodone, Hydromorphone, Meperidine, Methadone, Morphine, Oxycodone, Oxymorphone, Tapentadol, Tramadol
Mechanism of toxicity: Increased stimulation of opioid receptors
Receptor and Clinical effects
u – Analgesia, sedation, euphoria, respiratory, depression, GI dysmotility, bradycardia, pruritis, physical dependence
k – Analgesia, miosis
g – Analgesia
Opioid Overdose: Clin Presentation
Sedation
Respiratory distress
Bradycardia
Hypotension
Miosis
Emesis
Constipation
Seizures (meperidine, tramadol)
Overdose Treatment: Naloxone (Narcan)
MOA: Competitively inhibits binding of opioids to opioid receptors
Goals of therapy: Reinstitution of spontaneous ventilation
Use lower practical dose; escalate rapidly as clinically indicated
IV: 0.4-2 mg as initial dose
Repeat dose at 2-3 minute intervals
Consider other causes of toxicity if no response after 10mg of naloxone
Adverse Reaction: Withdrawal
Pharmacokinetics: T1/2 = 30-90 minutes
Benzodiazepines and Barbiturates
Benzodiazepines and Barbiturates: Clin Presentation
Benzodiazepines and Barbiturates: Management and Monitoring
Supportive Care
Maintain airway
Hemodynamic support
Minimum 24h monitoring period for overdoses on long-acting hypnotics or drugs with significant enterohepatic recirculation
Benzodiazapine Antidote: Flumazenil
MOA: Competitive benzodiazepine antagonist
Rapidly reverses sedative effect of benzodiazepines and Zolpidem
Dose:
0.2mg over 30 seconds
Repeat doses: 0.2 mg over 30 seconds repeated at 1-min intervals
Maximum Cumulative Dose: 3mg (usual total dose 1-3 mg)
Caution: May precipitate benzo withdrawal
Boxed Warning: Seizures
Caution in multi-substance overdoses
Beta Blocker & Calcium Channel Blocker Toxicity
Beta Blockers
B1 selective: Acebutolol, Atenolol, Betaxolol, Bisoprolol, Esmolol, Metoprolol, Nebivolol
Mixed: Carvedilol, Labetalol, Propranolol
Calcium Channel Blockers
Dihydropyridine: Amlodipine, Nicardipine, Nifedipine, Nimodipine
Non-dihydropyridine: Verapamil, Diltiazem
Beta Blocker & Calcium Channel Blocker Toxicity Clinical Presentation
Bradycardia
Hypotension
CCB-Specific
Vasodilatory shock
Hyperglycemia
Dihydropyridines: Reflex tachycardia in mild – moderate overdose
BB-Specific
Propranolol: Hypoglycemia, seizures, coma, and dysrhythmias
Prolonged QRS and QT intervals
Rare: Prolonged PR interval or high-grade AV block
Beta Blocker & Calcium Channel Blocker Mechanism of Toxicity
BB/CCB Supportive care
Early airway and respiratory support
Early GI decon
Activated charcoal (single dose) for all IR ingestions if within 4 hours
Whole Bowel irrigation (polyethylene glycol electrolyte mixture) for SR preparations if early and Asymptomatic
Manage Shock
Isotonic IV fluids: Limit 1-2 L to avoid fluid overload and pulmonary edema
Symptomatic bradycardia
Cutaneous and transvenous pacing
BB/CCB Pharmacotherapy PT 1 (Atropine/Calcium)
BB/CCB Pharmacotherapy PT 2 (Glucagon)
BB/CCB Pharmacotherapy PT 3 (Catecholamines)
BB/CCB Pharmacotherapy PT 4 (High-dose insulin euglycemia therapy (HIET))
Specific Pharmacotherapy
Monitoring
Observe in the ICU until bradycardia, hypotension, EKG abnormalities, and/or CNS Toxicity resolve
Beta Blockers
Toxicity from regular release beta blockers poisoning typically occurs within the first 6 hours
Sotalol: Delayed ventricular dsyrhythmias up to 9 hours post-ingestion
Observe PTs who ingest ER preparations for at least 24 Hours
Calcium Channel Blockers
If IR preparation ingestion, ensure that serial EKGs over 6-8 Hours have remained unchanged
Observe PTs who ingest ER products for at least 24 Hours, even if asymptomatic
Digoxin
Cardioactive steroid used for management of supraventricular arrhythmias and heart failure
MOA:
Inhibition of the Na/K/ATPase pump in myocardial cells
Increased intracellular Ca via Na/Ca exchange pump
Increased myocardial contractility