toxicology

Question 1

what should not be given as an antidote to TCA OD

Answer 1

physostigmine

**can cause heart block or asystole

Question 2

most toxic beta blocker

Answer 2

propanolol

Question 3

high levels of beta blockers can block what channels

Answer 3

sodium

Question 4

beta blocker OD sxs

Answer 4

lipophilic – cross CNS = seizures and coma

bradycardia
hypotension

Question 5

pindolol OD sxs

Answer 5

hypertension

tachycardia

Question 6

IV glucagon for beta blocker OD tx does what

Answer 6

inc cAMP

Question 7

TCA toxicity: CA reuptake inhibition

Answer 7

tachycardic

hypertensive

Question 8

TCA anticholinergic effects

Answer 8

sedation

coma

Question 9

TCA alpha blockade effects

Answer 9

hypotension

Question 10

TCA on cardiac myocytes

Answer 10

quinidine like blockade of cardiac fast sodium channels

QRS widening

slowed conduction and depressed cardiac contractility

inhibits VG K+ channels = QT prolongation

Question 11

TCA toxicity management

Answer 11

sodium bicarb for quinidine like toxicity

NE - for hypotension

never give physostigmine

Question 12

hyperthermia
myoclonic jerking
muscle rigidity

Answer 12

serotonin syndrome

Question 13

tx serotonin syndrome

Answer 13

cyproheptadine

5HT2 antagonist

Question 14

nalmefene

Answer 14

opioid OD tx

Question 15

naloxone

Answer 15

opioid OD tx

Question 16

theophyline acute intoxication

Answer 16

vomiting/hematemesis
coarse tremor, anxiety
tachycardia
metabolic acidosis: hypokalemia, low PO4, high Ca2+, high glucose

SEVERE - seizures (most common in acute), hypotension, arrhythmias

Question 17

theophylline chronic intoxication

Answer 17

**dysrhythmias (more common with chronic)

minimal GI sxs, less likely to have seizures

Question 18

theophylline OD tx

Answer 18

propranolol, esmolol

benzo/barb for seizures

Question 19

sulfonylurea/meglitinides OD tx

Answer 19

IV dextrose

octreotide

Question 20

hyperthermia
lead pipe rigidity
metabolic acidosis
confusion

Answer 20

neuroleptic malignant syndrome

Question 21

neuroleptic malignant syndrome tx

Answer 21

physical cooling tx

benzo for agitation

dantroline, bromocriptine, amantadine - unknown effectiveness

Question 22

formic acid

Answer 22

toxicity of methanol poisoning

causes acidosis, retinal damage, and blindness

methanol directly –> CNS depression

Question 23

fomepizole

Answer 23

compeitiive inhib of alcohol dehdyrogenase = dec production of formic acid

Question 24

ethanol use in methanol toxicity

Answer 24

competitive inhibitor of alcohol dehdyrogenase = dec production of formic acid

Question 25

ethylene glycol toxicity

Answer 25

metabolized to aldehdyes and oxalate: acidosis renal damage GI sxs Ca2+ oxalate crystals

Question 26

ethylene glycol toxicity tx

Answer 26

fomepizole ethanol if acidotic: sodium bicarb same as methanol poisoning

Question 27

pralidoxime

Answer 27

splits phosphate enzyme bond as the pesticide has phosphorylated AchE postively charged - doesn't cross BBB, no reversal of CNS effects

Question 28

carbamates

Answer 28

inhibit AchE by carbamoylation of active site

Question 29

carbamate OD tx

Answer 29

atropine

Question 30

warfarin OD tx

Answer 30

vitamin K - doesn't restore for 6 or more hours initally give fresh frozen plasma or whole blood

Question 31

Cyanide toxicity

Answer 31

binds Fe3+ strongly - prevents from serving as electron acceptor

Question 32

CN OD tx: antidote kit

Answer 32

provide pool of ferric iron to compete with CN cyanide antidote kit: - amyl nitrite pearls: inhale - sodium nitrite: IV - sodium thiosulfate (donate sulfur to form thiocyanate via rhodanese) forms methemoglobin --> cyanmethemoglobin and cyochrome oxidase is restored give methylene blue

Question 33

CN OD tx: cyanokit

Answer 33

hydroxocobalamin (B12 precursor) --> reacts with CN to form cyancobalamin **no methemoglobin produced

Question 34

lead OD tx

Answer 34

seizures - diazepam cerebral edema - mannitol, dexamethasone chelation

Question 35

arsenic poisoning

Answer 35

pyruvate dehydrogenase complex sensitive to trivalent arsenicals pentavalent: uncouple oxidative phosphorylation hemolysis via depletion of glutathione

Question 36

arsenic OD tx

Answer 36

ACUTE - chelate: dimercaprol (w/in 24 hours), unithiol CHRONIC - succimer or unithiol (after 24 hours) supportive: IV hydration, osmotic diuresis with mannitol - maintain urine output

Question 37

acute mercury poisoning tx

Answer 37

unithiol IM dimercaprol oral succimer

Question 38

chronic mercury poisoning tx

Answer 38

unithiol and succimer dimercaprol may redistribute mercury to CNS - NOT USED

Question 39

vomiting GI bleedings lethargy gray cyanosis

Answer 39

iron toxicity

Question 40

iron chelator

Answer 40

deferoxamine