Antianxiety drugs: sedative and hypnotics -- Benzodiazepine

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Antianxiety drugs: sedative and hypnotics -- Benzodiazepine
2013-07-11 16:50:56

Antianxiety drug
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  1. Antianxiety
    Reduction of apprehension and excitement . . .

    more selectively than during sedation
  2. Sedation
    Reduction of apprehension and excitement . .

    with minimal alteration of coordination and mental status
  3. Hypnosis
    Induction of sleep . . .

    approximating the normal physiologic state
  4. Anxiety in the U.S.
    •Most common psychiatric disorder

             8%of population will have anxiety D/O in any given 6 month

    •Common reason to avoid the dentist

    • •Dentists treat short-term anxiety as a
    • symptom rather than as a disorder

    •Rx night before and/or morning of appointment
  5. Anxiety Disorders
    • •Emotional Pain or Feeling All Is Not Well
    •          Feeling of Impending Doom

    • •May Not Have Conscious Focus
    •            Fear: Aware of What The Problem Is

    • •With or Without Somatic Features
    •           Tachycardia, Palpitations, Headaches, Sweating, Chest Pain

    Include phobia, panic attack and PTSD
  6. Irrational Fear That Interferes With Normal Behavior
  7. Sudden, Overwhelming Sense of Terror
    Panic Disorder
  8. Phobia vs. Panic attack
    • Phobia:
    • •Agoraphobia
    • •Social Phobias: Public Speaking,
    • Embarrassment
    • •Simple Phobias: Snakes, Heights, Needles,
    • Dentistry

    • Panic attacks:
    • •15% Cardiology Patients Diagnosed With
    • Panic
    • •Acute Phase Usually Lasts 20 – 30 Minutes
  9. Anxiety Disorders: Treatment
    •Cognitive-Behavioral Therapy


    •Medications: SSRIs, Benzodiazepines, Buspirone, Antihistamines, (Beta Blockers)
  10. Benzodiazepines
    Antianxiety drugs: Alprazolam(Xanax), Diazepam (Valium), Lorazepam (Ativan)

    • Sedative-hypnotics:Temazepam
    • (Restoril),Triazolam (Halcion)

    Anticonvulsants: Clonazepam (Klonopin), Clorazepate (Tranxene)

    •Anesthetic: Midazolam (Versed)
  11. History of Benzodiazepines
    •Developed in 1960s, became very popular

    •Diazepam was most commonly prescribed for over 15 years

    •Alprazolam is now the most prescribed

    •15% of adults take a benzodiazepine at least once per year
  12. Benzodiazepine - mechanism
    •Binding to benzodiazepine (w) receptor on the GABAa receptor complex

    • •Interaction with GABA
    •               improved GABA binding to GABAA receptor site
    •               enhanced GABA effect on chloride channel; increases frequency of channel opening (Cl- influx)

    Picrotoxin antagonize the effect
  13. Benzodiazepine effect
    • •Antianxiety effect
    •            Occurs at 1/10th dose of hypnotic effect in studies
    •            Alprazolam antidepressant & antipanic effects

    •CNS depression (dose-dependent)

    •Anticonvulsant action

    •Centrally mediated muscle relaxation

    •Anterograde amnesia

    • •Minimal cardiovascular depression
    • i.e. cardiac output, blood pressure

    • •Inhibition of stage 4 sleep (“night
    • terrors”)
  14. Benzodiazepine - adverse effect
    • •Respiratory depression
    • Minimal unless combined with other drugs

    •Drowsiness: can be benefit or not

    •Paradoxical excitement

    •Vascular irritation with IV injection (diazepam)

    •Drug abuse (class IV): class II in NY State

    •Narrow-angle glaucoma exacerbation

    • •Teratogenesis (category D, X)
    • Do not withhold in status epilepticus
  15. Benzodiazepine - Therapeutic use
    • Acute and chronic anxiety relief
    • Perioperative sedation
    • Acute insomnia
    • Alcohol withdrawal
    • Muscle relaxation
    • Seizures
    • Panic disorders and depression
  16. Drug interactions - Flumazenil (Romazicon)
    • a specific benzodiazepine antagonist

  17. Drug interaction - other CNS depressants
    Summation effects
  18. Drug interaction - Opioids
    Enhancement of respiratory depression
  19. drug interaction -- erythromycin and other CYP3A4 inhibitors
    Impaired metabolism
  20. drug interaction -  smokers, rifampin, carbamazepine
    decrease effect
  21. Benzodiazepine's antagonist -- [Flumazenil (Romazicon)]
    Specific benzodiazepine antagonist

    Can reverse sedation within 2 minutes

    Used to treat benzodiazepine overdoses

    • Can precipitate withdrawal in patients dependent on benzodiazepines, who have
    • epilepsy, or take tricyclics

    Very slight inverse activity
  22. Benzodiazepine's inverse agonist
    Compounds that act at the benzodiazepine receptor sites but yield opposite pharmacologic effects

    Can inhibit the action of a conventional agonist and a receptor that is constitutively active

    Negative intrinsic activity
  23. Selective BZ1-Receptor  Agonists (mechanism)
    Specific agents: Zolpidem (Ambien), Zaleplon (Sonata), Eszopiclone (Lunesta)

    • •Mechanism of action: Stimulation
    • of specific benzodiazepine receptors
  24. Selective BZ1-Receptor Agonists (pharmacological effect)
    •Rapid onset: 10-20 min (zolpidem, zaleplon)

    • •Short duration
    • Zolpidem half-life 2.5 hours
    • Zaleplon half-life 1 hour
    • Not eszopiclone; half-life 6 hours

    •Less amnesia, good sedative effects

    •Minimal anticonvulsant and muscle relaxant effects

    •Moderate antianxiety effect

    •Pregnancy category B (zolpidem), C (zaleplon)

    •Preserves sleep architecture better than benzo’s

    •Reversible with flumazenil