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Questions and Answers
Victims of suicide are usually found dead at the scene or die shortly thereafter.
Victims of suicide are usually found dead at the scene or die shortly thereafter.
True
Benzodiazepines have a low therapeutic index, making them very dangerous in overdose cases.
Benzodiazepines have a low therapeutic index, making them very dangerous in overdose cases.
False
At extremely high doses, benzodiazepines can cause neuromuscular blockade.
At extremely high doses, benzodiazepines can cause neuromuscular blockade.
True
Chloral hydrate poisoning displays symptoms similar to benzodiazepine intoxication.
Chloral hydrate poisoning displays symptoms similar to benzodiazepine intoxication.
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Antihistamines primarily cause CNS stimulation in overdose situations for adults.
Antihistamines primarily cause CNS stimulation in overdose situations for adults.
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In children, antihistamine overdose typically leads to central stimulation, hallucinations, and hyperpyrexia.
In children, antihistamine overdose typically leads to central stimulation, hallucinations, and hyperpyrexia.
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The treatment of depressant poisoning prioritizes cosmetic procedures to improve patient appearance.
The treatment of depressant poisoning prioritizes cosmetic procedures to improve patient appearance.
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Benzodiazepine overdose patients typically demonstrate more cognitive issues than motor performance problems.
Benzodiazepine overdose patients typically demonstrate more cognitive issues than motor performance problems.
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Chloral hydrate is converted to tri-chloro-ethanol, which is its active metabolite.
Chloral hydrate is converted to tri-chloro-ethanol, which is its active metabolite.
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The main side effect of benzodiazepines at any dosage is general anesthesia.
The main side effect of benzodiazepines at any dosage is general anesthesia.
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Short-acting barbiturates have a duration of action between 12 to 24 hours.
Short-acting barbiturates have a duration of action between 12 to 24 hours.
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Intermediate acting barbiturates, like amobarbital, have a duration of 8 to 10 hours.
Intermediate acting barbiturates, like amobarbital, have a duration of 8 to 10 hours.
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Short-acting barbiturates reach higher CNS concentrations due to their low lipid solubility.
Short-acting barbiturates reach higher CNS concentrations due to their low lipid solubility.
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Phenobarbital is more difficult to eliminate from the body than short-acting barbiturates during overdose.
Phenobarbital is more difficult to eliminate from the body than short-acting barbiturates during overdose.
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Respiratory depression is a minor toxic event following barbiturate ingestion.
Respiratory depression is a minor toxic event following barbiturate ingestion.
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Hypothermia is caused by the stimulant action of barbiturates on the thermo-regulatory center.
Hypothermia is caused by the stimulant action of barbiturates on the thermo-regulatory center.
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Symptoms of barbiturate poisoning may include decreased gastrointestinal motility.
Symptoms of barbiturate poisoning may include decreased gastrointestinal motility.
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Lethal doses of long-acting barbiturates produce death in a short period of time.
Lethal doses of long-acting barbiturates produce death in a short period of time.
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Barbiturates act directly on gamma-amino-butyric acid (GABA) to produce a stimulating effect.
Barbiturates act directly on gamma-amino-butyric acid (GABA) to produce a stimulating effect.
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Higher doses of barbiturates may lead to reduced blood pressure due to sympathetic ganglia depression.
Higher doses of barbiturates may lead to reduced blood pressure due to sympathetic ganglia depression.
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A cuffed endotracheal tube is not required in Stage 4 coma to prevent aspiration pneumonia during lavage.
A cuffed endotracheal tube is not required in Stage 4 coma to prevent aspiration pneumonia during lavage.
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The prevention of further absorption of poison can include using Ipecac to induce vomiting.
The prevention of further absorption of poison can include using Ipecac to induce vomiting.
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Gastric lavage should not be performed on a comatose individual.
Gastric lavage should not be performed on a comatose individual.
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Activated charcoal is ineffective in adsorbing barbiturates and common CNS-depressant drugs.
Activated charcoal is ineffective in adsorbing barbiturates and common CNS-depressant drugs.
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Alkalinization enhances the excretion of weak acids like barbiturates by promoting their ionization.
Alkalinization enhances the excretion of weak acids like barbiturates by promoting their ionization.
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Multiple doses of activated charcoal are most effective if administered immediately after phenobarbital ingestion.
Multiple doses of activated charcoal are most effective if administered immediately after phenobarbital ingestion.
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Flumazenil can effectively terminate the effects of benzodiazepines regardless of the dose administered.
Flumazenil can effectively terminate the effects of benzodiazepines regardless of the dose administered.
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Hemodialysis is consistently effective in removing CNS depressants from the blood after toxic ingestion.
Hemodialysis is consistently effective in removing CNS depressants from the blood after toxic ingestion.
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Signs of uremia may indicate the need for hemoperfusion or hemodialysis.
Signs of uremia may indicate the need for hemoperfusion or hemodialysis.
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Cardiovascular function should be assessed promptly after ingesting massive doses of CNS depressants.
Cardiovascular function should be assessed promptly after ingesting massive doses of CNS depressants.
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Study Notes
Clinical Toxicology: Barbiturates
- Barbiturates are divided into three types:
- Short-acting: duration of action 4-6 hours (e.g., secobarbital, pentobarbital)
- Intermediate-acting: duration of action 8-10 hours (e.g., amobarbital)
- Long-acting: duration of action 12-24 hours (e.g., phenobarbital)
- Short-acting barbiturates are associated with increased, not decreased, toxicity
- Toxic blood concentrations of phenobarbital are more easily reduced by hemodialysis and alkaline diuresis compared to short-acting barbiturates
Mechanism of Barbiturate Toxicity
- Barbiturates act directly on GABA (gamma-aminobutyric acid) like effects or stimulate GABA release
- GABA is an inhibitory neurotransmitter in the CNS
- Release of GABA leads to central depression
Barbiturate Poisoning Characteristics
- Respiratory depression is a major cause of death after barbiturate ingestion
- Hypothermia can occur due to depressant action on the thermoregulatory center
- Toxicity can induce acidosis, hypoxia, and shock
- Larger doses can depress sympathetic ganglia, reducing blood pressure
- Decreased gastrointestinal motility and tone can increase drug absorption
Benzodiazepines
- Benzodiazepines have a wide therapeutic index, making them the safest sedative-hypnotics
- Increasing doses do not cause general anesthesia, unlike other sedative drugs.
- Toxicity is primarily due to sedative effects on the central nervous system (CNS)
- High doses can cause neuromuscular blockade
- Benzodiazepines are selective for polysynaptic pathways
- Inhibit presynaptic transmission by stimulating the inhibitory neurotransmitter GABA
- Effects on motor performance are more pronounced than cognitive effects
Benzodiazepine Poisoning Characteristics
- On occasion, patients may experience paranoia, psychosis, hallucinations, or hypomania
Chloral Hydrate
- Widely used sedative for both adults and children
- Metabolized to trichloroethanol
- Both chloral hydrate and trichloroethanol are lipid-soluble and easily cross the blood-brain barrier
- Poisoning resembles barbiturate intoxication
- Corrosive action can cause gastritis, nausea, and vomiting
Antihistamines
- Antihistamines can cause sedation
- Adults often experience overdose resulting in CNS depression
- Children may experience central stimulation instead of depression
- Side effects can include dry mouth, mydriasis, flushed skin, fever, blurred vision, as well as hallucinations, tonic-clonic convulsions, and hyperpyrexia
CNS Depression Overdose Management
- Stabilizing respiratory function and correcting anoxia (lack of oxygen) is paramount
- Oxygen and mechanical ventilation are crucial
- Endotracheal intubation (with a cuffed tube) may be necessary for severe cases to reduce the risk of aspiration pneumonia
- The patient should be repositioned frequently to avoid hypostatic pneumonia
Treatment of CNS Depression Overdose
- Preventing further absorption of the poison is essential
- Methods include emesis using ipecac, gastric lavage in comatose patients, and activated charcoal administration which binds to barbiturates and other CNS depressants
- Increasing excretion is achieved through alkalinization techniques, promoting drug ionization and more rapid excretion. Multiple doses of activated charcoal may reduce blood concentrations, and hemodialysis can significantly remove CNS depressants in severe cases
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Description
This quiz focuses on the clinical aspects of barbiturates, including their classification into short-, intermediate-, and long-acting types. It covers the mechanism of barbiturate toxicity, the characteristics of poisoning, and the severe effects associated with barbiturate ingestion. Test your knowledge on these vital concepts in toxicology.
