Benzodiazepines Overview and Classification

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Questions and Answers

What is the significance of the high therapeutic index of benzodiazepines compared to barbiturates?

It makes them less likely to cause dependence.

It allows for a wider dosage range before toxicity occurs. (correct)

It indicates they are more effective as first-line medications.

It reduces the risk of overdose in chronic users.

Which benzodiazepine is classified as an ultrashort acting agent?

Alprazolam

Lorazepam

Temazepam

Midazolam (correct)

How does lorazepam effectively address status epilepticus when IV access is difficult?

It can be administered orally for quick absorption.

It is the only benzodiazepine with an active prodrug form.

It is the most potent benzodiazepine available.

It can be given intramuscularly for slower absorption. (correct)

Which term describes the process by which benzodiazepines are metabolized into inactive metabolites?

Conjugation Signup and view all the answers

What is a common consequence of chronic benzodiazepine use?

Development of tolerance and dependence. Signup and view all the answers

What is the role of the GABAA receptors in the action of benzodiazepines?

They mediate interaction through binding at the alpha subunit. Signup and view all the answers

What does the pharmacokinetic property of 'redistribution' in benzodiazepines imply?

They accumulate in body fat after initial distribution. Signup and view all the answers

Which of the following benzodiazepines is known to be primarily administered intravenously?

Diazepam Signup and view all the answers

What is the primary effect of benzodiazepines on GABAA receptors?

They increase the frequency of opening of the chloride channel. Signup and view all the answers

Which of the following is NOT a common presentation of benzodiazepine overdose?

Profound coma with significant hypotension Signup and view all the answers

In the context of benzodiazepine overdose treatment, which of the following interventions is performed FIRST?

Supportive measures Signup and view all the answers

Which specific antidote is used for reversing the effects of benzodiazepines?

Flumazenil Signup and view all the answers

What type of investigation is specifically used to measure benzodiazepine concentrations in a patient?

Serum benzodiazepine concentration via GCMS Signup and view all the answers

Which method of gastrointestinal decontamination should be used if the patient is alert and has an intact gag reflex?

Emesis Signup and view all the answers

What is a rare but serious complication of isolated benzodiazepine overdose?

Death Signup and view all the answers

Which of the following is a method that can be used for elimination of benzodiazepines from the bloodstream?

Forced alkaline diuresis Signup and view all the answers

Study Notes

Benzodiazepines (BZ)

BZ are the most commonly prescribed psychotropic drugs
They are often preferred to barbiturates and other toxic agents due to their higher therapeutic indices
Chronic use of BZ 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 that is converted to the active form, Nordazepam.
IV: Midazolam is commonly used intravenously during anesthesia; Diazepam is also used in IV form for anesthesia and anticonvulsant purposes
IM: Slow absorption; Lorazepam may be used in status epilepticus if IV access is difficult

Pharmacokinetics - Distribution

Distributed throughout the body, crossing the blood-brain barrier and placental barrier
Accumulate in body fat over time
Highly bound to plasma proteins

Pharmacokinetics - Metabolism

Most BZ are metabolized through oxidation, followed by conjugation with glucuronic acid, often producing active metabolites.
Some BZ, like Nitrazepam and Clonazepam, directly conjugate with glucuronic acid, forming inactive metabolites

Pharmacokinetics - Excretion

Excreted in urine after conjugation with glucuronic acid

Mechanism of Action

BZ bind to specific BZ receptors located on the alpha subunit of GABA_A receptors with high affinity
This binding increases the frequency of opening of GABA_A chloride channels

Benzodiazepines (BZ) Toxicity - Clinical Presentation

CNS depression: The primary effect of BZ overdose. Symptoms range from drowsiness to profound coma; however, it is less severe than a barbiturate overdose
Low grade coma
Ataxia
Stupor
Profoud coma and life-threatening complications are uncommon with isolated BZ overdose
Death from isolated BZ overdose is rare but possible

Benzodiazepines (BZ) Toxicity - Investigations

Routine: CBC, Electrolytes, ABG, Renal function tests.
Specific: Serum BZ concentrations using GCMS or immunoassays.

Benzodiazepines (BZ) Toxicity - Treatment

I. Supportive: Airway management (intubation), respiration support, circulation stabilization, monitoring and maintaining vital functions
II. GIT Decontamination: Emesis, gastric lavage (with cuffed endotracheal tube), activated charcoal (MDAC), cathartics
III. Elimination of the poison from blood: Alkaline diuresis (for prolonged-acting agents); hemodialysis/hemoperfusion may be considered in severe or refractory cases.

Benzodiazepines (BZ) Toxicity - Antidotes

Flumazenil (Anexatel): A competitive BZ receptor antagonist; effective in reversing the effects of BZ overdose
Disadvantage: Should not be used for combined BZ and other drug toxicities, particularly if seizures are present.

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Description

Explore the world of benzodiazepines, the commonly prescribed psychotropic drugs known for their efficacy and therapeutic index. This quiz covers various benzodiazepines, their classification by duration of action, and pharmacokinetics. Test your knowledge on this important topic in psychopharmacology.