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75 Cards in this Set
- Front
- Back
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what are the most common ingestants in the US
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Analgesics: APAP, salicylates, NSAIDS.
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what are the most common fatal OD in the US
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Sedative/hypnotics/antipsychotics
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what are the forms of toxic reaction mechanisms
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1. affect the acquisition of or utilization of oxygen (e.g. hydrogen sulfid or CO or methemoglobin forms)
2. if it affects oxygen, is this effect mediated locally (e.g. simple asphyxiant like methane displacing alveolar oxygen) or does it affect systemic processes (HCN) 3. toxin depletes glucose or other essential substrates 4. cause cellular injury via free radical formation and lipid peroxidation (e.g. acetaminophen forming a reactive elctrophile NAPQI) 5. does the toxin result in formation of a metabolite that is more toxic than parent compound (ethylene glycol to glycolic acid or methanol to formic acid) 6. does the toxin reveal an underlying metabolic or enzymatic defect (G-6-PD) |
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how does APAP cause damage
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forms NAPQI via CYP2E1 which is detoxified endogenoously by scavenger of glutathione (binds to glutathione sulfur). in OD glutathione reserves are depleted and the toxic metabolite binds to hepatic macromolecules. main site of organ injury is the liver.
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what is the antidote for APAP
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NAC (N-acetylcysteine) promotes additional glutathione synthesis and may offer a substitute target for NAPQI
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what is methemoglobinemia
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Fe3+ hemoglobin formed from oxidizing Fe2+ state Hb
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what is the antidote for methemoglobinemia
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methylen blue is an antidote that reduces methemoglobin back to functional Hb. but b/c methylene blue needs to be reduced by NADPH which is made by G6PD, the antidote doesn't work for people with a G6PD deficiency
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what are methemoglobin formers
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numerous agents, mainly organic nitrite and nitrate compounds
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what's bad about Gyromitra mushrooms
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hydrazines in mushrooms inhibiti pyridoxing phosphokinase = no pyridoxine for GABA channel synthesis = seizures
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what's the gyromitra mushroom cure
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pyridoxine vit B6 antidote. (hydrazines in mushrooms inhibit pyridoxine phosphokinase = no pyridoxine for GABA channel synthesis = seizures)
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what does INH OD do
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INH inhibits pyridoxine phosphokinase = no pyridoxine for GABA channel synthesis = seizures
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INH OD antidote
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pyridoxine vit B6. INH inhibits pyridoxine phosphokinase = no pyridoxine for GABA channel synthesis = seizures
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what is the most common cause of drug-induced seizures
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alcohol (ethanol) withdrawal (others causes include cocaine, MDMA, INH)
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how do you treat alcohol seizure withdrawal
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thiamine then dextrose
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MOA for black widow spider venom
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black widow aka latrodectus spider = alpha latrotoxin which binds to presynaptic cation channel = opens them = influx= ACh release. reuptake is also inhibited
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crotalinae (pit vipers) and elapidae (coral snakes) venom MOA
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inhibit ACh release same as botulinum toxin
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botulinum toxin MOA
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cleaves vesicle attachment proteins = inhibit ACh release
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Neuroleptic malignant syndrome major criteria
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DA antagonism is MOA
1. recent use of antipsychotic drug or other DA alterer 2. fever w/o any other cause 3. muscle rigidity 4. elevated CK (muscle fiber damage) 5. autonomic instability (2 or more of sweating, tachycardia, elevated or depressed BP) |
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drugs that cause NMS
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DA antagonism. recent use of antipsychotic drug or other DA alterer. ziprasidone, haloperidol, fluphenazine
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Serotonin syndrome criteria
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1. cog/behav: confusion, disorientation, agitation, coma
2. autonomic dysfunction: hyperthermia, diaphoresis (too much sweat), tachycardia, tachypnea 3. neuromuscular: myoclonus, hyperreflexion, muscle rigidity, tremors |
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what causes serotonin syndrome
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SSRI + MAOI
SSRI + dextromethorphan paroxetine + meperidine (demerol, an opioid analgesic drug SSRI + CAD SSRI (e.g. venlafaxine which is a very potent SSRI)) |
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what are two things that cause hair loss
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radiation and thallium can cause alopecia
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what causes miosis
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opiates/opioids and organophosphate insecticides
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what causes mydriasis
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anticholinergics, cocaine and amphetamines. (cocaine blocks reuptake of NE, amphetamines cause NE release)
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what are some things that case bradycardia
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calcium channel antagonist OD, beta-blocker OD, organophosphate insecticide
bradycardia is a a part of the chlinergic toxidrome |
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cholinergic toxidrome mechanism and symptoms
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too much ACh. DUMBBBBEL
diarrhea, urination , miosi, bradycardia, bronchorrhea, bronchoconstriction, bradynea, emesis (vomiting), lacrimation you can die from the Bs |
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what is the antidote for the cholinergic toxidrome
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atropine, muscarinic antagonist which treats bradycardia from any cause cause it stops vagal influence on SA node
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what can tachycardia be caused by
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amphetamines, cocaine, and other sympathomimetics and tricyclic antidepressantts
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how do tricyclic antidepressants cause tachycardia
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poison sodium channel causing wide QRS (widened ro delayed depolarization) on ECG and also poison the K channel leading to QTc prolongation (prolonged repolarization)
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what is the anticholinergic toxidrome
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dry as a bone( dry mouth & skin); red as a beet (flushed skin); blind as a bat (dilated pupils and loss of accommodation); mad as a hatter (central anticholinergic mania); hot as hades (hot, dry skin less able to release heat); full as a flask (urinary retention and full bladder)
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what is the antidote for anticholinergic toxidrome
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pysostigmine salicylate which crosses BBB and is a reversible acetylcholinesterase inhibitor.
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what are some untoward effects of physostigmine salicylate
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may induce arhythmias so administer slowly and put on heart monitor. short duration of action = may have to readminister. should not be used with TC antidep OD because can cause lethal arrhythmias
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what causes cholinergic toxidrome
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organophosphate can cause it
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what is the opiate toxidrome
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pinpoint pupils (miosis), respiratory depression, CNS depression
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what is opiate toxidrome caused by
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opiates like heroin, codeine, diphenoxylate, propoxyphone
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what is opiate toxidrome antidote
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naloxone.
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activated charcoal indication
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no data that says that helps poisoing. don't give to person wwho can't protect their own airway.
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what are some causes of anion gap metabolic acidosis
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M (methanol); U (uremia); D (diabetic ketoacidosis (also alcoholic)); P (Phenols); I (iron, INH, inborn errors, inhaled solvents (toluene); L (lactic acidosis from shock, sepsis, etc, E (ethylen glycol, ethanol), S (salicylates)
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what is anion gap formula
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Na - (Cl- + CO2); normal is 14. if higher than 1 this means there are too many anions floating around in the blood
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what is osmolarity formula
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2Na + BUN/2.8 + BS/18. this is the calculated osm. what the person should have
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what is osmolar gap
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its used to estimate blood level of toxin that exerts osmotic force (ie how much drug is in the blood). osmolar gap = [measured osm]-[calculated osm]
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how do you use osmolar gap to estimate the drug concentrations in a patient's blood
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Level (mg/dL) = osmolar gap x MW/10
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what can cause false positive THC
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efavirenz
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what can cause false positive amphetamines
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sympathomimetics like cold medicine
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what can cause false positive PCP
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diphenydramine
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what is acetaminophen metabolism like
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metabolized mostly by glucoronidation and sulfation but the minor metabolic pathway via CYP2E1 forms the toxic metabolite
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are salicylates easily dialyzable?
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yes b/c MW less than 500 and Vd is low
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what is the MOA of salicylate OD
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interfere with kreb cycle = limit ATP production; affect proton porter function in mitochondria b/c they uncouple oxphos in OD (=hyperpyrexia). form organic acids = anion-gap metabolic acidosis.
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what is iron OD overdose
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deferoxamine mesylate chelates iron
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what is iron MOA
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when free in the blood it catalyzes redox reaction causing lipid peroxidation + free radical formation
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what does deferoxamine do to you adverse effect?
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vin rose color urine. chronic use has high frequency hearing loss, visual loss as well as yersinia sepsis and mucormycosis (fungal infection)
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what are some neural tube defect causes
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carbamazepine (CBZ) and valproic acid (VPA) can lead to neural tube defects so theya re teratogenic
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what does digoxin MOA
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works on Na+/K+ ATPase pump and poisons it in OD thus leading to hyperkalemia
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what is used as a digoxin antidote
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Fab antibody can be used as an antidote
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what does beta-blocker OD do
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it can cause bradycardia, hypotension, and low blood glucose
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how do you treat beta-blocker OD
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glucagon which bypasses blocked beta receptor to increase cyclic AMP which enhances calcium flux thru calcium channels and increases the rate and strength of myocardial contraction. treats hypoglycemia because it stimulates heaptic gluconeogenesis and glycogenolysis
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what is methanol's OD MOA?
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formic acid
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what is methanol OD cure?
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formic acid formation can be prevented by inhibiting ADH with fomepizole or ethanol. prevents formation of toxic metabolites thus buying time while the parent molecule is excreted unchanged or removed by hemodialysis
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what is ethylene glycol's MOA
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forms toxic metabolite glycolic acid, glycoxylic acid and oxalic acids =severe metabolic acidosis and renal toxicity. oxalate complexes wtih serum and tissue calcium = hypocalceia
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ethylene glycol antidote
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glycolic acid formation can be prevented by inhibiting ADH with fomepizole or ethanol. prevents formation of toxic metabolites thus buying time while the parent molecule is excreted unchanged or removed by hemodialysis
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what does isopropanol cause
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it cause ketosis not metabolic acidosis. alcohol dehydrogenase makes acetone from isopropanol. acetone and increasing ketosis.
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wwhat makes you at risk for aspiration pneumonitis
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aliphatic hydrocarbons.
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what makes you at risk for leukemia
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aromatic hydrocarbons
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what does toluene cause
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distal renal tubular acidosis and brain atrophy
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what is CO MOA
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hypoxia via interfering with Hb function
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what is CN mechanism
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hypoxia from poisoning cytochromes
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what is cyanide #1 choice antidote
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hydroxocobalamin whihc attracts cyanide to form cyanocobalamin
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how do you treat snakebites
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Fab antivenom
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what do brown recluse spider bites cause
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loxoscleles are dermonnecrotic
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what quality does lionfish marine toxin have
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heat labile
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what does ciguatera poisoning lead to
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cold-hot temperature sensation reverseal
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what is the MOA of most mushroom fatalities in north america
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cyclopeptide species such as amantin phalloides have amanitin toxin which inhibits RNA polymerase II leading to decrease in mRNA and protein transcription leading to cell death
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what are the most common pathogens for food poisoning
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staphylococci, campylobacter, and salmonella.
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what food poisoning is especially toxic
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E. coli 0157:H7 can cause hemolytic uremic syndrome which is due to verotxoin causing blood vessel damage, hemolysis and kidney failure
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what is botulism classic dx criteria
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descending paralysis; classic emg finidng is brief, small, abundant motor unit action potentials after repetitive stimulation
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