Poisoning - Toxicology Flashcards by Lindsey Herrera

What is the most rapid and complete method of stomach emptying?

gastric lavage

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Name 2 emesis-producing drugs.

1) ipecac 2) Apomorphine

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What happens in acetaminophen poisoning after 72-96 hours?

Peak hepatotoxicity

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Acidify urine with ____ or _____ to trap weak bases [pKa 7.5-10.5] like phencyclidine or amphetamine.

NH4Cl; ascorbic acid

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Death from methanol is almost always preceded by ______ and results from ______.

blindness; sudden cessation of respiration

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Hepatocellular injury via acetaminophen poisoning occurs via the eventual depletion of cellular glutathione and ______.

the binding of NAPQI to critical protein or cellular constituents

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How is the volume of distribution used in toxic drug doses?

predicts which drugs will be removed by dialysis/exchange transfusion

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What is the mechanism of action for ipecac?

local irritation and CNS stimulation of chemoreceptor zone (CTZ)

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Acidify urine with NH4Cl or ascorbic acid to trap weak bases [pKa 7.5-10.5] like _____ or _____.

phencyclidine; amphetamine

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What are the symptoms of acetaminophen poisoning in the initial 24 hours?

nausea, vomiting, diaphoresis, abdominal pain

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The half life may be prolonged in toxic overdoses due to ______.

saturation of the elimination mechanisms

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_______ results in visual disturbances (“like being in a snowstorm”) occurring soon after onset of acidosis due to effects of formic acid on optic disc and retina.

Methanol poisoning

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When is N-acetylcysteine given?

12-36 after ingestion of acetaminophen poison

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Alkalinize urine with NaHCO3 to trap weak acids [pKa 3.0-7.5] like _____ or ______.

aspirin; barbiturates

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Magnesium citrate or sulfate is contraindicated in ____ or _____.

renal disease or nephrotoxic poisons

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Name 4 pharmacokinetic/toxicokinetic strategies.

1) prevent/decrease absorption of toxin 2) inhibit toxification 3) enhance metabolism/detox 4) increase elimination

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What is the mechanism of action for Apomorphine?

a dopamine agonist, stimulates CTZ

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What are the symptoms of acetaminophen poisoning in after 7-8 hours?

severe liver damage and/or death

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Hepatocellular injury via acetaminophen poisoning occurs via _____ and the binding of NAPQI to critical protein or cellular constituents.

the eventual depletion of cellular glutathione

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Alkalinize urine with NaHCO3 to trap _____ [pKa ___-____] like aspirin or barbiturates.

weak acids; 3.0-7.5

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What is emesis?

emptying stomach rapidly

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What are the side effects of Apomorphine?

respiratory depression

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The rate-limiting enzyme in the ethanol metabolism pathway is _____.

alcohol dehydrogenase

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Why is it important to know clearance mechanisms/excretion in planning a treatment strategy?

to know the contribution of each organ to toxin elimination

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Ethylene glycol poisoning results in damage to the kidneys due to deposition of _____ leading to acute renal failure in most patients.

calcium oxalate crystals

\_\_\_\_\_ and ______ have minimal toxicity until metabolized to formic acid and oxalic acid.

Methanol; ethylene glycol

Name 3 treatments for EtOH poisoning.

1) suppress production of toxic metabolites by inhibiting alcohol dehydrogenase with ethanol or fomepizole 2) hemodialysis and gastric lavage 3) correction of metabolic acidosis with sodium bicarb

Alkalinize urine with ____ to trap weak acids [pKa 3.0-7.5] like aspirin or barbiturates.

NaHCO3

Sodium sulfate is contraindicated in _____ and \_\_\_\_\_.

congestive heart failure; hypertension

How are poisons chemically absorbed?

activated charcoal

What are the symptoms of acetaminophen poisoning after 24-48 hours?

hepatic damage: elevated plasma aminotransferases, prothrombin time prolonged

Toxic manifestations of _____ are due to enzyme inhibition and alteration of membrane structure (especially in _____ tissues).

heavy metals; neuronal

What is Hemoperfusion?

blood pumped thru a column of absorbent material

Methanol poisoning results in visual disturbances (“like being in a snowstorm”) occurring soon after onset of acidosis due to \_\_\_\_\_\_.

effects of formic acid on optic disc and retina

What is a gastric lavage?

Washing of stomach contents with saline and removal via nasogastric tube

Death from ______ is almost always preceded by blindness and results from sudden cessation of respiration.

methanol

Predisposing factors for hepatocellular damage are ______ and _______ (both occur with excessive alcohol consumption).

increased CYP2E1 activity; decreased hepatic glutathione content

When is Polyethylene glycol used?

in poisonings with sustained release drugs, metal ions, or drug packets

How is heavy metal toxicity treated?

chelating agents that complex with free metal ions in body fluids

What is given with activated charcoal to soften it?

sorbitol 70%

The _____ may be prolonged in toxic overdoses due to saturation of the elimination mechanisms.

half life

How does a toxic dose change absorption/bioavailability?

slow dissolving, altered GI emptying, injure GI tract

\_\_\_\_\_ is most effective for toxins with small Vd and low protein binding capacity.

Hemodialysis

Methanol and ethylene glycol have minimal toxicity until metabolized to _____ and \_\_\_\_\_.

formic acid; oxalic acid

Methanol poisoning results in visual disturbances (“\_\_\_”) occurring soon after onset of acidosis due to effects of formic acid on optic disc and retina.

like being in a snowstorm

What is the dose of activated charcoal?

10:1 of toxin every 4 hours

Acidify urine with NH4Cl or ascorbic acid to trap _____ [pKa \_\_\_-\_\_\_\_] like phencyclidine or amphetamine.

weak bases; 7.5-10.5

Predisposing factors for hepatocellular damage are increased CYP2E1 activity and decreased hepatic glutathione content (both occur with \_\_\_\_).

excessive alcohol consumption

What is fomepizole?

inhibitor of alcohol dehydrogenase

How does activated charcoal work?

binds the drug in gut

What is ipecac?

syrup that produces emesis after 15-30 min

Lavage + emesis removes about ____ of most oral poisons.

30%

Toxic manifestations of heavy metals are due to ____ and _____ (especially in neuronal tissues).

enzyme inhibition; alteration of membrane structure

Name a pharmacodynamic strategy.

antidotes

When is Hemoperfusion used?

high molecular weight toxins with poor water solubility

Hemodialysis is most effective for toxins with _____ and \_\_\_\_\_\_.

small Vd; low protein binding capacity

\_\_\_\_\_ results in damage to the kidneys due to deposition of calcium oxalate crystals leading to acute renal failure in most patients.

Ethylene glycol poisoning

The rate-limiting enzyme in the _____ metabolism pathway is alcohol dehydrogenase.

ethanol

Approximately ____ of acetaminophen goes through a phase II reaction; ____ proceeds through a phase I cytochrome P450 oxidation (CYP2E1).

70-80%; 5-10%

What does Polyethylene glycol do?

whole bowel content elimination

When are osmotic cathartics used?

if toxin ingestion was more than 1 hour ago, if it's in enteric coated caplets, or if it's hydrocarbon