CH 18 Depressants and Anesthetics

Chapter 18: Depressants

Types and Stages of Sleep

  • Types of Sleep:
    • Non-Rapid Eye Movement (NREM): Has four stages.
    • Rapid Eye Movement (REM): Associated with dreaming.
  • Insomnia: Defined as the inability to fall asleep or stay asleep.

Nonpharmacologic Management of Sleep Disorders

  • Guidelines to improve sleep:
    • Consistent waking time: Arise at the same hour each morning.
    • Limit daytime naps: Can disrupt nighttime sleep.
    • Avoid stimulants: Such as caffeine, alcohol, and nicotine at least 6 hours before bedtime.
    • Mindful eating and drinking: Avoid heavy meals, strenuous exercise, and large fluids before bedtime.
    • Pre-sleep routine: Engage in soothing activities like taking a warm bath or listening to quiet music.
    • Noise reduction: Minimize exposure to loud noises.

Sedative-Hypnotics

  • Definition: Medications that induce sedation and sleep.
  • Types of Sedative-Hypnotics:
    • Barbiturates: Older class of drugs; used short-term due to side effects such as tolerance.
    • Benzodiazepines: Include drugs like Alprazolam and Lorazepam; act on GABA receptors to reduce anxiety and treat insomnia.
    • Non-benzodiazepines: E.g., Zolpidem; prescribed for short-term sleep issues.
    • Melatonin Agonists: E.g., Ramelteon; regulates circadian rhythms and is not a controlled substance.
General Side Effects of Sedative-Hypnotics
  • Residual drowsiness
  • Vivid dreams and nightmares
  • Drug dependence and tolerance
  • Excessive depression
  • Respiratory depression
  • Hypersensitivity reactions

Benzodiazepines

  • Common Drugs: Alprazolam, Estazolam, Lorazepam, Temazepam.
  • Usage: Manage anxiety and insomnia.
  • Adverse Reactions: Possible respiratory depression; patients should avoid alcohol.
  • Patient Education:
    • Nonpharmacologic strategies for sleep should be encouraged.
    • Gradual withdrawal from benzodiazepines is advised to avoid withdrawal symptoms.

Non-Benzodiazepines

  • Examples: Zolpidem.
  • Duration: Recommended for short-term use (less than 10 days).
  • Action: Works by inhibiting neurotransmitters, providing 6-8 hours of sleep.
Melatonin Agonists
  • Example: Ramelteon.
  • Mechanism: Targets melatonin receptors.
  • Side Effects: May include drowsiness, dizziness, fatigue, headaches, and even suicidal ideation.

Special Considerations for Older Adults

  • Prioritize non-pharmacologic treatments.
  • Uses of short-acting benzodiazepines that are safer (like Estazolam, Temazepam).
  • Avoid use of long-acting benzodiazepines (e.g., Flurazepam).
  • Recommendations for use: Limit to four times per week or less.

Anesthesia Overview

  • Types of Anesthetics:
    • General Anesthetics: Depress the CNS, used for loss of consciousness and pain relief.
    • Local Anesthetics: Provide localized pain relief while maintaining consciousness.
Balanced Anesthesia
  • Components:
    • Hypnotics given pre-operative to induce sleep.
    • Use of opioids or benzodiazepines for premedication.
    • Inhaled gases like nitrous oxide and oxygen.
    • Muscle relaxants if necessary.
Stages of General Anesthesia
  1. Stage 1: Analgesia
  2. Stage 2: Excitement or Delirium
  3. Stage 3: Surgical Anesthesia
  4. Stage 4: Medullary Paralysis

Clinical Judgment for Anesthetics

  • Preoperative Assessment: Importance of thorough evaluations including age, health disorders, and substance use.
  • Monitor patients' vital signs and response to anesthesia.
  • Awareness of potential side effects and manage appropriately.
Routes of Administration for Anesthetics
  • Inhalation: E.g., Halothane, Isoflurane.
  • Intravenous (IV): E.g., Ketamine for rapid action.
  • Topical: Used on skin or mucous membranes.
  • Local & Spinal: Target specific areas for localized pain control.
Adverse Effects Related to Anesthetics
  • Respiratory and cardiovascular depression, especially with general anesthetics.
  • Special emphasis on monitoring for hypotension and respiratory distress post-procedure.
Practice Questions Highlights (for Exam Prep)
  1. Identify potential interventions for patients on benzodiazepines or with sleep disorders.
  2. Evaluate signs indicating a need for patient education regarding sedative use (e.g., fluid intake and substance avoidance).
  3. Understand common risks associated with anesthesia types, especially in older adults.