Toxicology Week 1 Flashcards
When should a hospital referral happen?
- Moderate to severe exposure
- Intentional ingestion
What are the ABCs of management?
Airway
Breathing
Circulation
Dextrose/Decontamination
EKG/Elimination
What are non-pharm options for toxic exposures?
Inhalational - remove from exposure area
Topical/dermal - irrigation with soap/water
T/F: We should utilize the gag reflex to remove toxic substances
FALSE
Which substances will not bind to activated charcoal?
- Ionized metals (lithium)
- Alcohols
- Gasoline
What are some pearls of activated charcoal?
- Sorbitol can improve palatability (only with one dose)
- Must have protected airway
- 1g/kg
What are some side effects of activated charcoal?
Vomiting, black tarry stools
Which decontamination strategy is useful for body packers or XR products?
Whole bowel irrigation
T/F: WBI is always best given by mouth
FALSE: an NG tube will eliminate the need for large volume consumption
When should you use orogastric lavage?
- Potential to produce serious toxicity
- No antidotes
- Time window gives reason to believe agent may still be in the stomach
When should hemodialysis be used?
- Other strategies unavailable/ineffective
- Potential to produce serious toxicity
- Agent dialyzable
Basically last line
What does an anticholinergic toxidrome look like?
- Dry mucous membranes
- Flushed skin
- Confused
- Absent bowel sounds
- Dilated pupils
- Hyperthermia
- Tachycardia
What is the antidote to anticholinergics?
Physostigmine (anticholinesterase inhibitor)
0.5 - 2 mg IV
What does a sedative-hypnotic toxidrome look like?
- Normal vital signs
- Very sleepy but can be woken up (painful stimuli)
What does an adrenergic/sympathomimetic toxidrome look like?
- All vitals high
- Agitated
- Positive bowel sounds
- Diaphoretic
- Dilated pupils
- Tremor
- Agitated
- Seizures
What does an opioid toxidrome look like?
- Unresponsive to stimuli (even painful)
- Respiratory rate very low
- Pinpoint pupils
What does a cholinergic toxidrome look like?
- Salivation
- Lacrimation
- Urination
- Defecation
- Gastric cramps
- Emesis
- Pinpoint pupils
- Heavy oral secretions
- Confusion
- Bradycardia
- Bronchorrhea
- Bronchospasm
What are the most dangerous effects of the cholinergic toxidrome?
Killer Bs:
- Bradycardia
- Bronchorrhea
- Bronchospasm
How can we treat a cholinergic toxidrome?
Atropine 1 mg IV - titrate until bronchorrhea resolved
Pralidoxime - must administer before cholinesterase becomes inactivated
What are substances with unique toxidromes that we should always get a level for?
Acetaminophen (no toxidrome), salicylates
Which drugs will levels be important for treatment?
- Digoxin
- Vancomycin
- Phenytoin
- Lithium
- Acetaminophen
Which 3 receptors do opioids act on?
- Mu
- Kappa
- Delta
Which enzyme is important for codeine?
CYP2D6
How do you treat an opioid overdose?
- Administer antidote (naloxone)
- Protect airway
T/F: Intranasal naloxone will protect a patient’s airway immediately
FALSE: longer duration than IV but SLOWER onset
Which dose of naloxone would you use for a non-opioid dependent patient?
0.4 mg IV
Which dose of naloxone would you use for an opioid dependent patient?
0.04 mg IV, titrate to effect
(we do not want to precipitate withdrawal)
What should we do if a patient is unconscious again after initial bolus of naloxone?
Give 1/2 of effective dose as bolus
Give 2/3 of effective dose per hour
What is naloxone-induced pulmonary edema?
Catecholamine surge causing tachycardia, tachypnea, HTN
Blood shunts to lungs and causes fluid leakage into lungs
How can we treat naloxone-induced pulmonary edema?
Nitroglycerin, diuretics, positive pressure ventilation
(Support their breathing)
How can we prevent naloxone-induced pulmonary edema?
Smaller initial doses of naloxone (prevents surge)
What does loperamide overdose look like?
Opioid overdose with cardiac arrhythmias
Blockage of what transporter ehnances loperamide effects?
PGP (keeps it from crossing BBB)
How do we treat loperamide overdose?
Naloxone (respiratory depression)
(for cardiac disturbances:)
IV magnesium
Sodium bicarbonate
IV isoproterenol
Transcutaneous pacing
CPR, ACLS
How do we treat benzodiazepine overdose?
Monitoring, supportive care
(High therapeutic index, rare death)
What are symptoms of benzodiazepine withdrawal?
- Severe sleep disturbance
- Irritability
- Increased tension and anxiety
- Panic attacks
- Sweating
- Difficulty in concentration
- Dry retching and nausea
- Palpitations
- Headache
- Psychotic reaction
- Seizures
- Death
T/F: Benzodiazepine withdrawal is fatal but opioid withdrawal is not?
TRUE
What is the antidote for benzodiazepines?
Flumazenil
What is the dosing for flumazenil?
0.2 mg IV over 15 min
1-2 minute onset
Re-dosing maybe needed
How can a benzodiazepine overdose possibly kill you?
Respiratory depression
When should you use flumazenil?
- Procedural sedation (known PMH)
- Unintentional, pediatric exposure (with relative confidence of non-dependence)
What are some sources of salicylates?
- Pepto-Bismol
- Alka-Seltzer
- Icy hot
- Bengay
- Oil of wintergreen
What is an acute overdose of salicylates?
> 150 mg/kg
(>500 mg/kg life threatening)
How much methyl salicylate is in oil of wintergreen?
98g / 100mL
Why do we have concern with renally impaired patients?
Renal elimination plays a greater role in significant overdose and has an extended half-life
What are s/s of salicylate overdose?
- Fast/shallow breathing
- N/V, volume depletion
- Hypoglycemia in brain
- Tinnitus
- Non-cardiogenic pulmonary edema (chronic)
- Renal/hepatic injury
What will help with CNS abnormalities in salicylate overdose?
Dextrose
What acid/base progression can be seen in salicylate overdose?
Respiratory alkalosis -> metabolic and respiratory acidosis (breathing cannot compensate)
What labs can be seen in salicylate overdose?
- Abnormal blood sugar (but HYPOglycemia in brain)
- Fluid/electrolyte losses
- Increased anion gap
- Positive urine ketones (utilized for energy)
What does a chronic salicylate overdose look like?
More insidious onset
- N/V, tinnitus, dyspnea, hyperthermia, neurologic problems
- Increased PT/LFTs
- Lower levels will produce toxic effects (higher Vd)
How could you treat salicylate overdose?
DO NOT INTUBATE
- Take multiple salicylate levels
- Multiple doses of activated charcoal
- Urine alkalization (pH > 7.5)
- Hemodialysis
- Treat adverse effects (seizures, cerebral edema, hypoglycemia, dysrhythmias)
What supportive care should be given for salicylate overdose?
- Give dextrose (even with normal glucose 0.5-1 g/kg)
- Fluid maintenance (serum pH 7.45-7.55)
- Urine pH > 7.5
- Maintain potassium
- Monitor (mental status, urine/blood pH, salicylate levels, fluid, electrolytes)
How often should monitoring be done in salicylate overdose?
Every 2-4 hours
When should hemodialysis be used in salicylate overdose?
- Serum level (acute >100mg/dL, chronic >60mg/dL)
- Neurologic deterioration
- Seizures
- Intractable acidosis (pH < 7.20)
- Renal failure
- Pulmonary edema
When can you stop hemodialysis
- Clear improvement in patient
- Salicylate <19 mg/dL
- HD completed for 4-6 hours and levels not obtainable