1 / 40

CHAPTER 12 Central Nervous System Depressants and Muscle Relaxants

CHAPTER 12 Central Nervous System Depressants and Muscle Relaxants . CNS Depressants . Sedatives or Hypnotics. CNS Depressants . Sedatives Drugs that have an inhibitory effect on the CNS to the degree that they reduce: Nervousness Excitability Irritability without causing sleep.

ostinmannual
Télécharger la présentation

CHAPTER 12 Central Nervous System Depressants and Muscle Relaxants

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CHAPTER 12Central Nervous System Depressants and Muscle Relaxants Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  2. CNS Depressants Sedatives or Hypnotics Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  3. CNS Depressants Sedatives • Drugs that have an inhibitory effect on the CNS to the degree that they reduce: • Nervousness • Excitability • Irritability without causing sleep Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  4. CNS Depressants (cont'd) Hypnotics • Calm or soothe the CNS to the point that they cause sleep • A sedative can become a hypnotic if it is given in large enough doses Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  5. CNS Depressants (cont'd) Sedative-hypnotics—dose dependent • At low doses, calm or soothe the CNS without inducing sleep • At high doses, calm or soothe the CNS to the point of causing sleep Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  6. Sleep • Normal sleep is cyclic and repetitive • A sleeping person is unaware of sensory stimuli within the immediate environment • Rapid eye movement (REM) • Non–rapid eye movement (non-REM) • Sleep stages Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  7. Table 12-2 Stages of Sleep Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  8. Sedative-Hypnotics: Barbiturates • First introduced in 1903; standard agents for insomnia and sedation • Habit forming • Only a handful commonly used today due in part to the safety and efficacy of benzodiazepines Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  9. Barbiturates: Four Categories • Ultrashort • mephobexital, thiamylal, thiopental • Short • pentobarbital, secobarbital • Intermediate • butabarbital • Long • phenobarbital, mephobarbital Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  10. Therapeutic Index • Dosage range within which the drug is effective but above which is rapidly toxic • Barbiturates have a very narrow therapeutic index Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  11. Table 12-3 Barbiturates: Onset and Duration Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  12. Barbiturates: Mechanism of Action • Site of action • Brainstem (reticular formation) • By inhibiting GABA, nerve impulses traveling in the cerebral cortex are also inhibited Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  13. Barbiturates: Drug Effects • Low doses: sedative effects • High doses: hypnotic effects (also lowers respiratory rate) • Notorious enzyme inducers • Stimulate liver enzymes that cause the metabolism or breakdown of many drugs Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  14. Barbiturates: Indications • Hypnotic • Sedative • Anticonvulsant • Anesthesia for surgical procedures Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  15. Barbiturates: Side Effects Body SystemEffects CNS Drowsiness, lethargy, vertigo, mental depression, coma Respiratory Respiratory depression, apnea, bronchospasms, cough Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  16. Barbiturates: Side Effects (cont'd) Body SystemEffects GI Nausea, vomiting, diarrhea constipation Other Agranulocytosis, vasodilation, hypotension, Stevens-Johnson syndrome Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  17. Barbiturates: Side Effects (cont'd) • Reduce REM sleep, resulting in: • Agitation • Inability to deal with normal stress Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  18. Barbiturates:Toxicity and Overdose • Overdose frequently leads to respiratory depression, and subsequently, respiratory arrest • Overdose produces CNS depression (sleep to coma and death) • Can be therapeutic • Anesthesia induction • Uncontrollable seizures: “phenobarbital coma” Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  19. Barbiturates:Drug Interactions • Additive effects • ETOH, antihistamines, benzodiazepines, narcotics, tranquilizers • Inhibited metabolism • MAOIs will prolong effects of barbiturates • Increased metabolism • Reduces anticoagulant response, leading to possible clot formation Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  20. Common Barbiturates • butabarbital (Butisol) • pentobarbital (Nembutol) • phenobarbital (Luminal) • secobarbital (Seconal) Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  21. CNS Depressants: Benzodiazepines Most frequently prescribed sedative-hypnotics • Most commonly prescribed drug classes • Favorable side effect profiles • Efficacy • Safety Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  22. Benzodiazepines: Classification • Classified as either: • Sedative-hypnotic • anxiolytic (medication that relieves anxiety) Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  23. Benzodiazepines:Sedative-Hypnotic Types • Long acting • estazolam (Prosom), quazepam (Doral) • Short acting • flurazepam (Dalmane), temazepam (Restoril) • triazolam (Halcion) Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  24. CNS Depressants: Nonbenzodiazepine Hypnotics Zalepion (Sonata) and zolpidem (Ambien) • Share many characteristics of benzodiazepines Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  25. Benzodiazepines:Mechanism of Action • Depress CNS activity • Affect hypothalamic, thalamic, and limbic systems of the brain • Benzodiazepine receptors • Do not suppress REM sleep as much as barbiturates do • Do not increase metabolism of other drugs Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  26. Benzodiazepines:Drug Effects • Calming effect on the CNS • Useful in controlling agitation and anxiety • Reduce excessive sensory stimulation, inducing sleep • Induce skeletal muscle relaxation Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  27. Benzodiazepines:Indications • Sedation • Sleep induction • Skeletal muscle relaxation • Anxiety relief • Treatment of alcohol withdrawal Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  28. Benzodiazepines:Indications (cont'd) • Agitation • Depression • Epilepsy • Balanced anesthesia Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  29. Benzodiazepines: Side Effects Mild and infrequent • Headache • Drowsiness • Dizziness • Vertigo • Lethargy • Paradoxical excitement (nervousness) • “Hangover effect” Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  30. CNS Depressants: Nursing Implications • Before beginning therapy, perform a thorough history regarding allergies, use of other medications, health history, and medical history • Obtain baseline vital signs and I&O, including supine and erect BPs • Assess for potential disorders or conditions that may be contraindications, and for potential drug interactions Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  31. Nursing Implications • Give 15 to 30 minutes before bedtime for maximum effectiveness in inducing sleep • Most benzodiazepines (except flurazepam) cause REM rebound and a tired feeling the next day; use with caution in the elderly • Patients should be instructed to avoid alcohol and other CNS depressants Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  32. Nursing Implications • Check with physician before taking any other medications, including OTC medications • It may take 2 to 3 weeks to notice improved sleep when taking barbiturates • Rebound insomnia may occur for a few nights after a 3- to 4-week regimen has been discontinued Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  33. Nursing Implications • Safety is important • Keep side rails up or use bed alarms • Do not permit smoking • Assist patient with ambulation (especially the elderly) • Keep call light within reach • Monitor for side effects Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  34. Nursing Implications • Monitor for therapeutic effects • Increased ability to sleep at night • Fewer awakenings • Shorter sleep-induction time • Few side effects, such as hangover effects • Improved sense of well-being because of improved sleep Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  35. Muscle Relaxants • Act to relieve pain associated with skeletal muscle spasms • Majority are central acting • CNS is the site of action • Similar in structure and action to other CNS depressants • Direct acting • Acts directly on skeletal muscle • Closely resembles GABA Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  36. Muscle Relaxants: Indications • Relief of painful musculoskeletal conditions • Muscle spasms • Management of spasticity of severe chronic disorders • Multiple sclerosis, cerebral palsy • Work best when used along with physical therapy Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  37. Muscle Relaxants: Indications (cont'd) • dantrolene • Malignant hyperthermia crisis Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  38. Muscle Relaxants: Side Effects • Extension of effects on CNS and skeletal muscles • Euphoria • Lightheadedness • Dizziness • Drowsiness • Fatigue • Muscle weakness Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  39. Common Muscle Relaxants • baclofen (Lioresal) • cyclobenzaprine (Flexeril) • dantrolene (Dantrium) • metaxalone (Skelaxin) • tizanidine (Zanaflex) Mosby items and derived items © 2005, 2002 by Mosby, Inc.

  40. Muscle Relaxants: Nursing Implications • See others listed for CNS depressants Mosby items and derived items © 2005, 2002 by Mosby, Inc.

More Related