Benzodiazepines [Neurosurgery Wiki]

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====== Benzodiazepines ======

Benzodiazepines (BZDs) are a class of psychoactive drugs with anxiolytic, sedative, muscle relaxant, anticonvulsant, and hypnotic properties. They act by enhancing the effect of gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter in the central nervous system.

===== Classification =====
  * **Drug class:** Central nervous system depressants
  * **ATC code:** N05BA (anxiolytics), N05CD (hypnotics), N03AE (antiepileptics)
  * **Schedule:** Controlled substances in most countries (e.g., Schedule IV in the U.S.)

===== Mechanism of Action =====
  * Bind to the **benzodiazepine site** on the **GABA-A receptor**
  * Increase the **frequency** of chloride channel opening → **hyperpolarization** of the neuron → reduced excitability

===== Clinical Uses =====
  * **Anxiety disorders** (e.g., generalized anxiety disorder, panic disorder)
  * **Insomnia** (short-term use)
  * **Seizure control** (e.g., status epilepticus)
  * **Muscle spasms**
  * **Alcohol withdrawal**
  * **Procedural sedation**
  * **Adjunctive treatment in tinnitus-related distress** (off-label)

===== Common Benzodiazepines =====
  * **Short-acting:** Midazolam, Triazolam
  * **Intermediate-acting:** Lorazepam, Alprazolam, Oxazepam
  * **Long-acting:** Diazepam, Clonazepam, Chlordiazepoxide

===== Adverse Effects =====
  * **Common:** Drowsiness, dizziness, confusion, impaired coordination
  * **Cognitive:** Anterograde amnesia, slowed psychomotor performance
  * **Dependence and withdrawal** with long-term use
  * **Risk of falls** and **delirium** in the elderly
  * **Respiratory depression** in overdose or when combined with other CNS depressants

===== Contraindications =====
  * History of **substance use disorder**
  * Severe **hepatic impairment**
  * **Sleep apnea**
  * **Myasthenia gravis**
  * Use with **opioids** (risk of fatal respiratory depression)

===== Monitoring =====
  * Monitor sedation level, respiratory status (especially if IV)
  * Reassess regularly for continued need
  * Taper gradually to avoid withdrawal

===== Special Considerations =====
  * Risk of **tolerance** and **dependence** increases with duration
  * Should be **avoided in elderly** (Beers Criteria) unless clearly indicated
  * Use lowest effective dose for the **shortest duration possible**

===== Reversal Agent =====
  * **Flumazenil** (competitive antagonist of the BZD receptor) — used in overdose or procedural reversal; risk of seizures

===== Synonyms =====
  * **BZD**, **benzos**
  * Not to be confused with **barbiturates** (different receptor modulation)

===== Related Concepts =====
  * [[antidepressants|Antidepressants]]
  * [[GABA_A receptor|GABA-A receptor]]
  * [[dependence|Dependence and withdrawal]]