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Questions and Answers
What is the primary effect of benzodiazepines on GABAA receptors?
What is the primary effect of benzodiazepines on GABAA receptors?
Which of the following is NOT a common presentation of benzodiazepine overdose?
Which of the following is NOT a common presentation of benzodiazepine overdose?
What is the role of Flumazenil in the treatment of benzodiazepine overdose?
What is the role of Flumazenil in the treatment of benzodiazepine overdose?
Which supportive treatment is essential for managing benzodiazepine overdose?
Which supportive treatment is essential for managing benzodiazepine overdose?
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What is the preferred method for gastrointestinal decontamination in benzodiazepine overdose if the patient is alert?
What is the preferred method for gastrointestinal decontamination in benzodiazepine overdose if the patient is alert?
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Which investigation is specific for measuring benzodiazepine concentrations in the blood?
Which investigation is specific for measuring benzodiazepine concentrations in the blood?
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In what circumstance would hemodialysis be considered in benzodiazepine overdose cases?
In what circumstance would hemodialysis be considered in benzodiazepine overdose cases?
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What is a critical prevention step in treating benzodiazepine overdose aside from antidotes?
What is a critical prevention step in treating benzodiazepine overdose aside from antidotes?
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Which of the following statements about benzodiazepines is true?
Which of the following statements about benzodiazepines is true?
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Which of the following benzodiazepines is classified as having an ultrashort duration of action?
Which of the following benzodiazepines is classified as having an ultrashort duration of action?
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What is the primary route through which benzodiazepines are administered for rapid effect in anesthesia?
What is the primary route through which benzodiazepines are administered for rapid effect in anesthesia?
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Which mechanism describes how benzodiazepines exert their effects?
Which mechanism describes how benzodiazepines exert their effects?
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How are most benzodiazepines metabolized in the body?
How are most benzodiazepines metabolized in the body?
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What is the primary form of excretion for benzodiazepines?
What is the primary form of excretion for benzodiazepines?
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Which benzodiazepine is NOT classified as a long-acting drug?
Which benzodiazepine is NOT classified as a long-acting drug?
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What characteristic is true regarding the distribution of benzodiazepines in the body?
What characteristic is true regarding the distribution of benzodiazepines in the body?
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Study Notes
Benzodiazepines (BZ)
- Benzodiazepines are the most commonly prescribed psychotropic drug.
- They are considered to have high therapeutic indices, replacing barbiturates and other toxic agents as first-line anxiolytics and hypnotics.
- Chronic use can lead to tolerance and dependence.
Common Benzodiazepines
- Diazepam (Valium)
- Lorazepam (Ativan)
- Flunitrazepam (Rohypnol)
- Bromazepam (Calmipam)
- Clonazepam (Rivotrill)
- Midazolam (Dormicum)
Classification by Duration of Action
- Ultrashort (<6h): Triazolam, Midazolam
- Short (12-18h): Lorazepam, Oxazepam, Temazepam
- Medium (24h): Alprazolam, Nitrazepam
- Long (24-48h): Diazepam, Clonazepam, Chlordiazepoxide, flurazepam
Pharmacokinetics: Absorption
- Oral: Well absorbed; chlorazepate is a prodrug, metabolized to the active form, nordazepam, in the stomach.
- IV: Midazolam is used for IV anesthesia; Diazepam is used for IV anesthesia and as an anticonvulsant.
- IM: Slow absorption; lorazepam is often used in status epilepticus if IV access is difficult.
Pharmacokinetics: Distribution
- Distributed throughout the body, crossing the blood-brain barrier and placental barrier.
- Gradually accumulate in body fat.
- Highly bound to plasma proteins.
Pharmacokinetics: Metabolism
- Primarily metabolized through oxidation to produce active metabolites, followed by conjugation with glucuronic acid.
- Some benzodiazepines directly conjugate with glucuronic acid, yielding inactive metabolites. (e.g., Nitrazepam, Clonazepam).
Pharmacokinetics: Excretion
- Excreted in urine after conjugation with glucuronic acid.
Mechanism of Action
- Benzodiazepines (BZ) bind to BZ receptors located on the alpha subunit of GABAA receptors.
- This increases the frequency of opening at GABAA chloride channels.
Benzodiazepines (BZ) Toxicity
- Clinical Presentation (CP): Main presentation is CNS depression (less severe than barbiturates). Symptoms include drowsiness, stupor, ataxia, mild coma. Rarely profound coma, hypotension, respiratory depression or hypothermia occur in isolated BZ overdose.
- Severity of overdose: Death from isolated BZ overdose is rare, usually safer than barbiturate overdose.
- Investigations: Routine tests like CBC, Electrolytes, ABG, and RFT are performed. Serum BZ concentrations are measured using GCMS or immunoassays for diagnosis.
Treatment
- I. Supportive: Airway management (endotracheal intubation/assisted ventilation), shock control (IV fluids & dobutamine), warming blankets, coma cocktail (naloxone, thiamine, glucose), antibiotics.
- II. GIT Decontamination: Emesis (if alert and gag reflex present), gastric lavage (with cuffed endotracheal tube, within 12 hours post-ingestion), activated charcoal (multiple doses), cathartics (e.g., sorbitol).
- III. Elimination of the poison from blood: Forced alkaline diuresis (for long-acting barbiturates). Hemodialysis/hemoperfusion for serious cases with refractory hypotension and dense coma.
- IV. Antidotes: Flumazenil (Anexatel): a competitive BZ receptor antagonist. Effective within minutes for isolated BZ overdose, but not used for combined toxicity (BZ + drugs causing seizures).
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Description
Explore the essential details about benzodiazepines, including their classification, common types, and pharmacokinetics. This quiz covers the therapeutic uses and potential for tolerance and dependence associated with these drugs. Test your knowledge on how benzodiazepines are categorized by their duration of action and absorption methods.
