Benzodiazepines Overview

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What are benzodiazepines commonly prescribed for?

Benzodiazepines are commonly prescribed as anxiolytics and hypnotics.

What potential issue arises from the chronic use of benzodiazepines?

Chronic use may lead to tolerance and dependence.

Identify two examples of benzodiazepines classified as ultrashort-acting.

Triazolam and Midazolam are both classified as ultrashort-acting benzodiazepines.

Explain the primary route of excretion for benzodiazepines after metabolism.

Benzodiazepines are excreted in urine after conjugation with glucuronic acid. Signup and view all the answers

Describe the distribution characteristics of benzodiazepines in the body.

Benzodiazepines distribute all over the body, easily passing the blood-brain barrier and placental barrier. Signup and view all the answers

What is the mechanism of action of benzodiazepines?

Benzodiazepines exert their effects by binding to BZ receptors located at the alpha subunit of GABAA receptors. Signup and view all the answers

Which benzodiazepine is often used as an IV anesthetic?

Midazolam is commonly used as an IV anesthetic. Signup and view all the answers

How does chlorazepate differ from other benzodiazepines in terms of absorption?

Chlorazepate is a prodrug that is converted to Nordazepam, which is rapidly absorbed. Signup and view all the answers

What is the primary effect of benzodiazepines on GABAA receptors?

Benzodiazepines increase the frequency of opening at the GABAA chloride channel. Signup and view all the answers

What is the main clinical presentation of benzodiazepine overdose?

CNS depression is the main presentation of benzodiazepine overdose. Signup and view all the answers

How does the toxicity of benzodiazepines compare to barbiturates?

Benzodiazepine overdose is generally considered safer than barbiturate overdose. Signup and view all the answers

What supportive measures should be taken for a patient with benzodiazepine overdose?

Supportive care includes monitoring vital functions and possibly intubation for airway protection. Signup and view all the answers

Which investigation is used to determine serum benzodiazepine concentrations?

Serum benzodiazepine concentrations can be assessed using GCMS or immunoassays. Signup and view all the answers

What is the role of flumazenil in benzodiazepine overdose treatment?

Flumazenil is a competitive benzodiazepine receptor antagonist that reverses benzodiazepine effects. Signup and view all the answers

What is one method of gastrointestinal decontamination for benzodiazepine overdose?

Gastric lavage can be performed within 12 hours of ingestion if the patient is at risk. Signup and view all the answers

What specific treatment might be considered for long-acting benzodiazepine overdoses?

Multiple-dose activated charcoal (MDAC) may be utilized for long-acting benzodiazepines. Signup and view all the answers

Study Notes

Benzodiazepines (BZ)

Benzodiazepines (BZ) are frequently prescribed psychotropic drugs.
They are often preferred over barbiturates due to their higher therapeutic indices.
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

This classification is based on how long the drug's effects last.
- Ultrashort (<6 hours): Triazolam, Midazolam
- Short (12-18 hours): Lorazepam, Oxazepam, Temazepam
- Medium (24 hours): Alprazolam, Nitrazepam
- Long (24-48 hours): Diazepam, Clonazepam, Chlordiazepoxide, Flurazepam

Pharmacokinetics: Absorption

Oral: Well-absorbed; chlorazepate is a prodrug that becomes Nordazepam in the stomach (active form).
Intravenous (IV): Midazolam is commonly given intravenously for anesthesia; Diazepam is also given intravenously for anesthesia and anticonvulsant treatments.
Intramuscular (IM): Slow absorption; lorazepam is used in status epilepticus when IV administration is difficult.

Pharmacokinetics: Distribution

BZ distribute throughout the body, crossing the blood-brain barrier and placental barrier.
They accumulate in body fat.
Highly bound to plasma proteins.

Pharmacokinetics: Metabolism

Most BZ undergo oxidation to produce active metabolites, followed by conjugation with glucuronic acid.
Some BZ directly conjugate with glucuronic acid to form inactive metabolites (e.g., Nitrazepam, Clonazepam).

Pharmacokinetics: Excretion

BZ and their metabolites are excreted in urine after conjugation with glucuronic acid.

Mechanism of Action

BZ exert their effects by binding to BZ receptors located on the alpha subunit of GABA_A receptors.
This increases the frequency of GABA_A chloride channel opening.

Benzodiazepines (BZ) Toxicity: Clinical Presentation

Central Nervous System (CNS) depression: The primary sign of BZ overdose; less severe than barbiturate overdose. Symptoms include drowsiness, stupor, ataxia and low-grade coma.
Less commonly, there is profound coma, significant hypotension, respiratory depression, or hypothermia.
Death from isolated BZ overdose is rare.

Benzodiazepines (BZ) Toxicity: Investigations

Routine: Complete Blood Count (CBC), Electrolytes, Arterial Blood Gas (ABG), Renal Function Tests (RFT).
Specific: Serum BZ concentrations using gas chromatography-mass spectrometry (GCMS) or immunoassays.

Benzodiazepines (BZ) Toxicity: Treatment

I. Supportive: Airway management (intubation), maintaining vital signs (IV fluids). Includes precautions against a "coma cocktail" (including naloxone, thiamine and glucose) and antibiotics for pneumonia, if required.
II. Gastrointestinal (GIT) Decontamination: Emesis (if alert and gag reflex present), Gastric lavage (with endotracheal tube if compromised gag reflex), activated charcoal, multiple-dose activated charcoal (for long-acting drugs) and cathartics.
III. Elimination: Forced alkaline diuresis (for long-acting barbiturates). Hemodialysis or hemoperfusion may be necessary to remove the drug in cases of severe hypotension, coma, or dense coma, where the kidneys or liver are unable to metabolize the drug effectively.

Benzodiazepines (BZ) Toxicity: Antidotes

Flumazenil (Anexatel): A competitive BZ receptor antagonist that can reverse the effects of BZ.
Advantage: Effective within minutes for isolated BZ overdose.
Disadvantage: Not used in combined toxicity (BZs and drugs causing seizures)

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

This quiz covers the essential aspects of benzodiazepines, including their common types, classification based on duration of action, and pharmacokinetics. Learn about the therapeutic benefits and risks associated with these psychotropic drugs. Test your knowledge on their absorption methods and clinical uses.