Pharm: Muscle Relaxers

Central Nervous System Depressants and Muscle Relaxants

Sedatives

• Reduce nervousness, excitability, irritability.

Hypnotics

• Induce sleep; more potent than sedatives.

• Sedative can act as a hypnotic at high doses.

Sedative-Hypnotics

• Dose-dependent:

  • Low doses calm CNS without sleep.

  • High doses induce sleep.

• Classified into:

  • Barbiturates

  • Benzodiazepines

  • Miscellaneous drugs.

Sleep

• Decrease in physical activity and consciousness.

• Sleep architecture:

  • REM sleep

  • Non-REM sleep.

Benzodiazepines

• Function: sedative-hypnotic or anxiolytic.

• Commonly used for sedation, sleep induction, relaxation, and anxiety relief.

• Adverse effects include drowsiness, dizziness, cognitive impairment, and fall risks.

Benzodiazepines Mechanism

• Depress CNS activity, affect specific brain systems; modulate GABA receptors.

Toxicity/Overdose

• Leads to somnolence, confusion, coma, but not necessarily hypotension or respiratory depression, unless combined with other CNS depressants. Treatment is supportive.

Herbal Products

• Kava: relieves anxiety; possible hepatotoxic effects.

• Valerian: used for anxiety/insomnia; may cause CNS depression and hepatotoxicity.

Barbiturates

• Low therapeutic index and habit-forming.

• Classified by duration: ultrashort, short, intermediate, long-acting.

• Major indications: anesthesia, seizure control, sedation.

• Adverse effects include drowsiness, respiratory depression, and reduced REM sleep.

Muscle Relaxants

• Relieve muscle spasms and spasticity in chronic disorders.

• Adverse effects include sedation, dizziness, and muscle weakness.

Nursing Implications

• Monitor for therapeutic effects (e.g., improved sleep).

• Educate on dangers of combining with alcohol or other CNS depressants.

• Safety precautions for older adults are crucial (e.g., fall risks).