Benzodiazepines 1 Flashcards
Benzodiazepines - 11 drugs
Alprazolam Chlordiazepoxide Clonazepam Diazepam Estazolam Flurazepam Lorazepam Midazolam Oxazepam Tamazepam Triazolam
Benzodiazepines - MOA
Facilitates activity of GABAA receptor-chloride ion channel. Binds receptors with both α1 and α2 subunits. Increases the receptors affinity for GABA, and the frequency of when the channel is open. Increased chloride conductance causes hyperpolarization. GABA dependent.
Also inhibit neuronal reuptake of adenosine. Increases inhibitory effect of adenosine on neurons that release ACh → arousal.
Benzodiazepines - effects
Dose-dependent but limited CNS depression.
Sedative and anxiolytic effect. Hypnosis and anesthesia.
Anterograde amnesia Anticonvulsant effect.
Muscle relaxation.
Mild euphoric effect. Pharmacodynamic tolerance, cross-tolerance.
Dilation of coronary arteries and decreased total peripheral resistance (from adenosine reuptake inhibition).
Daytime sedation and hangover.
Suppress slow-wave and REM sleep.
Benzodiazepines - clinical use
Anxiety, insomnia.
Amnesic property for pts undergoing stressful procedures (endoscopy/outpatient surgery).
Seizure disorders.
Occasionally muscle spasm and spasticity.
Alcohol withdrawal.
Preferred short-term.
Benzodiazepines - contraindications
Driving. Use of other CNS depressant
Benzodiazepines - adverse effects
Anterograde amnesia. Motor incoordination, dizziness, excessive drowsiness. Impaired cognitive processing, concentration, judgment, planning. Interfere with driving and psychomotor skills. Drowsiness.
Respiratory depression (IV adm). Mild euphoria. Physical dependence (long-term use).
Fetal malformations
Benzodiazepines - Withdrawal syndrome
Nonleathal, headache, insomnia, rebound anxiety, irritability, muscle twitches.
Hypotension, arrhythmia (tachy & brady). Fatal massive overdose.
Benzodiazepine antagonist
Flumazenil: competitive benzo receptor antagonist.
β-carboline derivatives: inverse agonists
Flumazenil - adverse effects
Seizures, arrhythmias, blurred vision, emotional lability, dizziness.
Medium-acting benzodiazepines - 5 drugs
Alprazolam. Clonazepam. Estazolam. Lorazepam. Temazepam.
Short-acting benzodiazepines - 3 drugs
Midazolam
Oxazepam
Triazolam
Long-acting benzodiazepines - 3 drugs
Chlordiazepoxide
Diazepam
Flurazepam
Benzos with no active metabolites - 4 drugs
Clonazepam
Lorazepam
Oxazepam
Temazepam
Which benzodiazepines are safer in elderly pts and why? 3 drugs
Lorazepam.
Oxazepam.
Temazepam.
They bypass phase I oxidation, only phase II conjugation.
Which benzodiazepines are administered only orally? 7 drugs
Alprazolam Clonazepam Estazolam Flurazepam Oxazepam Temazepam Triazolam
