ANTIDOTES FOR THE USMLE &
COMLEX QUESTIONS AND ANSWERS
WITH SOLUTIONS 2024
acetaminophen (tylenol) - ANSWER *N-acetylcysteine*
MOA = restores glutathione
salicylates (aspirin) - ANSWER *NaHCO3*
MOA = urine alkalinization
if within 1 hour of ingestion → *activated charcoal*
MOA = prevents absorption
*theophylline*
(scenario = COPD patient presents w/ HA, nausea & vomiting, and coarse tremor; labs reveal
hypokalemia & metabolic acidosis; death results from intractable ventricular arrythmia) - ANSWER beta-
bockers (propanolol, esmolol)
*cholinesterase inhibitors*,
*organophosphates (e.g. parathion)*
(scenario = farmer exposed to insecticides) - ANSWER *1st line = atropine*
MOA = blocks ACh receptors
*pralidoxime (2-PAM)*
MOA = regenerates AChE if given early
*sarin gas*
, (scenario = Syrian child exposed to nerve gas during bombing;
or a soldier returning from WW1) - ANSWER *1st line = atropine*
MOA = blocks ACh receptors
*pralidoxime (2-PAM)*
MOA = regenerates AChE if given early
*anticholinergic/antimuscarinic toxicity*
(scenario = jimson weed in California) - ANSWER *physostigmine*
MOA = tertiary amine (can freely cross BBB); reverses CNS anticholinergic effects
*iron*
(scenario = child undergoing repeated transfusions for beta-thalassemia) - ANSWER
*deferoxamine/deferasirox/deferiprone*
MOA = binds trivalent (ferric) iron & increases its renal excretion
*lead*
(scenario = 2 y/o teething child begins chewing on household objects & becomes lethargic + clutches
abdomen; labs reveal ↑ free erythrocyte protoporphyrin level & basophilic stippling on peripheral
smear.) - ANSWER *1st line = succimer*
2nd line = penicillamine
if severe = calcium EDTA + dimercaprol
*carbon monoxide (CO)*
(scenario = found in garage w/ car running; cherry-red appearance) - ANSWER *100% oxygen*
consider Hyperbaric O2
COMLEX QUESTIONS AND ANSWERS
WITH SOLUTIONS 2024
acetaminophen (tylenol) - ANSWER *N-acetylcysteine*
MOA = restores glutathione
salicylates (aspirin) - ANSWER *NaHCO3*
MOA = urine alkalinization
if within 1 hour of ingestion → *activated charcoal*
MOA = prevents absorption
*theophylline*
(scenario = COPD patient presents w/ HA, nausea & vomiting, and coarse tremor; labs reveal
hypokalemia & metabolic acidosis; death results from intractable ventricular arrythmia) - ANSWER beta-
bockers (propanolol, esmolol)
*cholinesterase inhibitors*,
*organophosphates (e.g. parathion)*
(scenario = farmer exposed to insecticides) - ANSWER *1st line = atropine*
MOA = blocks ACh receptors
*pralidoxime (2-PAM)*
MOA = regenerates AChE if given early
*sarin gas*
, (scenario = Syrian child exposed to nerve gas during bombing;
or a soldier returning from WW1) - ANSWER *1st line = atropine*
MOA = blocks ACh receptors
*pralidoxime (2-PAM)*
MOA = regenerates AChE if given early
*anticholinergic/antimuscarinic toxicity*
(scenario = jimson weed in California) - ANSWER *physostigmine*
MOA = tertiary amine (can freely cross BBB); reverses CNS anticholinergic effects
*iron*
(scenario = child undergoing repeated transfusions for beta-thalassemia) - ANSWER
*deferoxamine/deferasirox/deferiprone*
MOA = binds trivalent (ferric) iron & increases its renal excretion
*lead*
(scenario = 2 y/o teething child begins chewing on household objects & becomes lethargic + clutches
abdomen; labs reveal ↑ free erythrocyte protoporphyrin level & basophilic stippling on peripheral
smear.) - ANSWER *1st line = succimer*
2nd line = penicillamine
if severe = calcium EDTA + dimercaprol
*carbon monoxide (CO)*
(scenario = found in garage w/ car running; cherry-red appearance) - ANSWER *100% oxygen*
consider Hyperbaric O2
