What do ED50, TD50, and LD50 stand for in terms of a particular pharmacologic agent?

Effective dose 50 Toxic dose 50 Lethal dose 50

BMB 3 - Toxidromes & Antidotes Flashcards by Jason Worley

What do ED₅₀, TD₅₀, and LD₅₀ stand for in terms of a particular pharmacologic agent?

Effective dose ₅₀

Toxic dose ₅₀

Lethal dose ₅₀

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What is the ED₅₀ for a pharmacologic agent?

The dose at which 50% of individuals experience the therapeutic effect

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What is the TD₅₀ for a pharmacologic agent?

The dose at which 50% of individuals experience toxicity

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What is the LD₅₀ for a pharmacologic agent?

The dose at which 50% of individuals are killed

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How is the therapeutic index calculated for a particular pharmacologic agent?

TD₅₀ / ED₅₀

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Which is safer, a high therapeutic index or a low therapeutic index?

High

(TI = TD₅₀ / ED₅₀)

(Higher TIs indicate a larger gap between toxic dosing and the lower doses at which efficacy is achieved.)

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Management of drug toxicities, overdoses, etc. should always start with what three things?

The ABCs

Airway

Breathing

Circulation

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A patient presents in an apparent coma. What should you administer?

Glucose

Insulin

Naloxone

(thiamin?)

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A patient presents while seizing.

What should you administer to stop the seizure?

Diazepam

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A patient presents with severe agitation.

What should you administer?

An anxiolytic

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In order of importance, name the three main laboratory methods for determining the cause of a poisoning.

Urine (first choice)
Blood/serum (second choice)
Gastric contents (third choice)

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A patient presents with lead poisoning.

What do you administer?

Dimercaprol

penicillamine

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A patient presents with arsenic poisoning.

What do you administer?

Dimercaprol

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A patient presents with mercury poisoning.

What do you administer?

Dimercaprol

penicillamine

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A patient presents with iron poisoning.

What do you administer?

Deferoxamine

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A patient presents with copper poisoning.

What do you administer?

Penicillamine

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A patient presents with heparin toxicity.

What do you do?

Administer protamine sulfate

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A patient presents with botulinum toxicity.

What do you do?

Administer antitoxin

provide respiratory support

A patient presents with organophosphate poisoning.

What do you do?

Administer atropine + pralidoxime

A patient presents with cyanide poisoning.

What do you do?

Administer amyl nitrate

(subsequent thiosulfate can increase excretion)

A patient presents with ethylene glycol poisoning.

What substances can be used to prevent its conversion to toxic metabolites?

Ethanol

Fomepizole

A patient presents with methanol poisoning.

What substances can be used to prevent its conversion to toxic metabolites?

Ethanol

Fomepizole

A patient presents with carbon monoxide poisoning.

What do you do?

Administer hyperbaric O₂

A patient presents with warfarin toxicity.

What do you do?

Administer fresh frozen plasma + vitamin K

A patient presents with opiate overdose. What do you do?

Administer **naloxone** | (and subsequent **naltrexone**)

A patient presents with curarine poisoning. What do you do?

Administer **cholinesterase inhibitors** | (to reverse the NMJ blockade)

A patient presents with methemogobulinemia due to nitrate poisoning. What do you do?

Administer **methylene blue** | (to reduce Fe³⁺ to Fe²⁺)

A patient presents with methemogobulinemia due to sulfa drugs. What do you do?

Administer **methylene blue** | (to reduce Fe³⁺ to Fe²⁺)

A patient presents with digitalis toxicity. What digoxin-antibody can you administer?

Digibind

A patient presents with a 5-fluorouracil overdose. What do you do?

Administer **thymidine**

A patient presents with anticholinesterase toxicity. What do you do?

Administer **atropine**

A patient presents with agitation, mydriasis, seizures, and hypertension. What toxidrome is on your differential?

**Sympathomimetic use** | (e.g. cocaine, amphetamines, PCP, etc.)

A patient presents with CNS depression, decreased reflexes, and hypotension. What toxidrome is on your differential?

**Sedative use** (e.g. alcohol, benzodiazepines, barbituates, etc.)

A patient presents with respiratory depression, hypothermia, pinpoint pupils, and hypotension. What toxidrome is on your differential?

**Opiate use** | (e.g. morphine, codeine, heroin, etc.)

A patient presents with agitation, mydriasis, fever, dry skin, flushing, and urinary retention. What toxidrome is on your differential?

**Anticholinergic use** (e.g. atropine, scopolamine, TCAs, etc.)

A patient presents with coma, fasciculation, salivation, lacrimation, and wheezing. What toxidrome is on your differential?

**Cholinergic use** (e.g. organophosphates, carbamates, nicotine, etc.)

A patient presents with diaphoresis, tinnitus, early alkalosis, and late acidosis. What toxidrome is on your differential?

**Salicylate use**

# Describe the S/Sy of the toxidrome caused by overdose with the following: **Sympathomimetics** | (e.g. cocaine, amphetamines, PCP, etc.)

Agitation, mydriasis, seizures, hypertension

# Describe the S/Sy of the toxidrome caused by overdose with the following: **Sedatives** (e.g. alcohol, benzodiazepines, barbituates, etc.)

CNS depression, decreased reflexes, hypotension

# Describe the S/Sy of the toxidrome caused by overdose with the following: **Opiates** | (e.g. morphine, codeine, heroin, etc.)

Respiratory depression, hypothermia, pinpoint pupils, hypotension

# Describe the S/Sy of the toxidrome caused by overdose with the following: **Anticholinergics** (e.g. atropine, scopolamine, TCAs, etc.)

Agitation, mydriasis, fever, dry skin, flushing, urinary retention

# Describe the S/Sy of the toxidrome caused by overdose with the following: **Cholinergics** (e.g. organophosphates, carbamates, nicotine, etc.)

Coma, fasciculation, salivation, lacrimation, wheezing

# Describe the S/Sy of the toxidrome caused by overdose with the following: **Salicylates**

Diaphoresis, tinnitus, _early_ alkalosis, _late_ acidosis.