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Cns depressants


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Cns depressants

  1. 1. Central Nervous System Depressants
  2. 2. CNS Depressants <ul><li>Sedatives </li></ul><ul><li>Drugs that have an inhibitory effect on the CNS to the degree that they reduce: </li></ul><ul><ul><li>Nervousness </li></ul></ul><ul><ul><li>Excitability </li></ul></ul><ul><ul><li>Irritability </li></ul></ul><ul><ul><li>without causing sleep </li></ul></ul>
  3. 3. CNS Depressants <ul><li>Hypnotics </li></ul><ul><li>Calm or soothe the CNS to the point that they cause sleep </li></ul>
  4. 4. CNS Depressants <ul><li>Sedative-Hypnotics—dose dependent: </li></ul><ul><li>At low doses, calm or soothe the CNS without inducing sleep </li></ul><ul><li>At high doses, calm or soothe the CNS </li></ul><ul><li>to the point of causing sleep </li></ul>
  5. 5. Sedative-Hypnotics: Barbiturates <ul><li>First introduced in 1903, standard agents for insomnia and sedation </li></ul><ul><li>Habit-forming </li></ul><ul><li>Only a handful commonly used today due in part to the safety and efficacy of: BENZODIAZEPINES </li></ul>
  6. 6. Sedative-Hypnotics: Barbiturates <ul><li>Four categories: </li></ul><ul><li>Ultrashort </li></ul><ul><ul><li>mephobexital, thiamylal, thiopental </li></ul></ul><ul><li>Short </li></ul><ul><ul><li>pentobarbital, secobarbital </li></ul></ul><ul><li>Intermediate </li></ul><ul><ul><li>aprobarbital, butabarbital </li></ul></ul><ul><li>Long </li></ul><ul><ul><li>phenobarbital </li></ul></ul>
  7. 7. Sedative-Hypnotics: Barbiturates <ul><li>Barbiturates have a very narrow therapeutic index. </li></ul><ul><li>Therapeutic Index </li></ul><ul><li>Dosage range within which the drug is effective but above which is rapidly toxic. </li></ul>
  8. 8. Sedative-Hypnotics: Barbiturates <ul><li>Mechanism of Action </li></ul><ul><li>Site of action: </li></ul><ul><ul><li>Brain stem (reticular formation) </li></ul></ul><ul><ul><li>Cerebral cortex </li></ul></ul><ul><li>By inhibiting GABA, nerve impulses traveling in the cerebral cortex are also inhibited. </li></ul>
  9. 9. Sedative-Hypnotics: Barbiturates <ul><li>Drug Effects </li></ul><ul><li>Low doses: Sedative effects </li></ul><ul><li>High doses: Hypnotic effects (also lowers respiratory rate) </li></ul><ul><li>Notorious enzyme inducers </li></ul>
  10. 10. Sedative-Hypnotics: Barbiturates <ul><li>Therapeutic Uses </li></ul><ul><li>Hypnotics </li></ul><ul><li>Sedatives </li></ul><ul><li>Anticonvulsants </li></ul><ul><li>Surgical procedures </li></ul>
  11. 11. Sedative-Hypnotics: Barbiturates <ul><li>Side Effects </li></ul><ul><li>Body System Effects </li></ul><ul><li>CNS Drowsiness, lethargy, vertigo mental depression, coma </li></ul><ul><li>Respiratory Respiratory depression, apnea, bronchospasms, cough </li></ul>
  12. 12. Sedative-Hypnotics: Barbiturates <ul><li>Side Effects </li></ul><ul><li>Body System Effects </li></ul><ul><li>GI Nausea, vomiting, diarrhea </li></ul><ul><li>Other Agranulocytosis, vasodilation, hypotension, Stevens-Johnson syndrome </li></ul>
  13. 13. Sedative-Hypnotics: Barbiturates <ul><li>Toxicology </li></ul><ul><li>Overdose frequently leads to respiratory depression, and subsequently, respiratory arrest. </li></ul><ul><li>Can be therapeutic: </li></ul><ul><ul><li>Anesthesia induction </li></ul></ul><ul><ul><li>Uncontrollable seizures: “phenobarbital coma” </li></ul></ul>
  14. 14. Sedative-Hypnotics: Barbiturates <ul><li>Drug Interactions </li></ul><ul><li>Additive effects: </li></ul><ul><ul><li>ETOH, antihistamines, benzodiazepines, narcotics, tranquilizers </li></ul></ul><ul><li>Inhibited metabolism: </li></ul><ul><ul><li>MAOIs will prolong effects of barbiturates </li></ul></ul><ul><li>Increased metabolism: </li></ul><ul><ul><li>Reduces anticoagulant response, leading to possible clot formation </li></ul></ul>
  15. 15. CNS Depressants: Benzodiazepines <ul><li>Most frequently prescribed sedative-hypnotics </li></ul><ul><li>Most commonly prescribed drug classes </li></ul><ul><li>Favorable side effects </li></ul><ul><li>Efficacy </li></ul><ul><li>Safety </li></ul>
  16. 16. CNS Depressants: Benzodiazepines <ul><li>Classified as either: </li></ul><ul><li>Sedative-hypnotic or Anxiolytic </li></ul><ul><li>(Medication that relieves anxiety) </li></ul>
  17. 17. CNS Depressants: Benzodiazepines <ul><li>Sedative-Hypnotic Type </li></ul><ul><li>Long-Acting: </li></ul><ul><ul><li>flurazepam (Dalmane), quazepam (Doral) </li></ul></ul><ul><li>Short-Acting: </li></ul><ul><ul><li>estazolam (Prosom), temazepam (Restoril), </li></ul></ul><ul><ul><li>triazolam (Halcion) </li></ul></ul>
  18. 18. CNS Depressants: Benzodiazepines <ul><li>Anxiolytic Type </li></ul><ul><li>alprazolam (Xanax) </li></ul><ul><li>chloridiazepoxide (Librium) </li></ul><ul><li>diazepam (Valium) </li></ul><ul><li>lorazepam (Ativan) </li></ul><ul><li>midazolam (Versed) </li></ul><ul><ul><li>zolpidem (Ambien) and zaleplon (Sonata) </li></ul></ul><ul><ul><li>(nonbenzodiazepine hypnotic agents, share characteristics) </li></ul></ul>
  19. 19. CNS Depressants: Benzodiazepines <ul><li>Mechanism of Action </li></ul><ul><li>Depress CNS activity </li></ul><ul><li>Affect hypothalamic, thalamic, and limbic systems of the brain </li></ul><ul><li>Benzodiazepine receptors </li></ul>
  20. 20. CNS Depressants: Benzodiazepines <ul><li>Drug Effects </li></ul><ul><li>Calming effect on the CNS </li></ul><ul><li>Useful in controlling agitation and anxiety </li></ul>
  21. 21. CNS Depressants: Benzodiazepines <ul><li>Therapeutic Uses </li></ul><ul><li>Sedation </li></ul><ul><li>Sleep induction </li></ul><ul><li>Skeletal muscle relaxation </li></ul><ul><li>Anxiety relief </li></ul><ul><li>Treatment of alcohol withdrawal </li></ul><ul><li>Agitation </li></ul><ul><li>Depression </li></ul><ul><li>Epilepsy </li></ul><ul><li>Balanced anesthesia </li></ul>
  22. 22. CNS Depressants: Benzodiazepines <ul><li>Side Effects </li></ul><ul><li>Mild and infrequent </li></ul><ul><li>Headache Drowsiness Dizziness Vertigo Lethargy Paradoxical excitement (nervousness) “Hangover effect” </li></ul>
  23. 23. CNS Depressants: Nursing Implications <ul><li>Before beginning therapy, perform a thorough history regarding allergies, use of other medications,health history, and medical history. </li></ul><ul><li>Obtain baseline vital signs and I & O, including supine and erect BPs. </li></ul><ul><li>Assess for potential disorders or conditions that may be contraindications, and for potential drug interactions. </li></ul>
  24. 24. CNS Depressants: Nursing Implications <ul><li>Give 15 to 30 minutes before bedtime for maximum effectiveness in inducing sleep. </li></ul><ul><li>Most benzodiazepines (except flurazepam) cause REM rebound and a tired feeling the next day; use with caution in the elderly. </li></ul><ul><li>Patients should be instructed to avoid alcohol and other CNS depressants. </li></ul>
  25. 25. CNS Depressants: Nursing Implications <ul><li>Check with physician before taking any other medications, including OTC medications. </li></ul><ul><li>It may take 2 to 3 weeks to notice improved sleep when taking barbiturates. </li></ul><ul><li>Abruptly stopping these medications, especially barbiturates, may cause rebound insomnia. </li></ul>
  26. 26. CNS Depressants: Nursing Implications <ul><li>Safety is important </li></ul><ul><ul><li>Keep side rails up </li></ul></ul><ul><ul><li>Do not permit smoking </li></ul></ul><ul><ul><li>Assist patient with ambulation (especially the elderly) </li></ul></ul><ul><ul><li>Keep call light within reach </li></ul></ul><ul><li>Monitor for side effects </li></ul>
  27. 27. CNS Depressants: Nursing Implications <ul><li>Monitor for therapeutic effects </li></ul><ul><ul><li>Increased ability to sleep at night </li></ul></ul><ul><ul><li>Fewer awakenings </li></ul></ul><ul><ul><li>Shorter sleep induction time </li></ul></ul><ul><ul><li>Few side effects, such as hangover effects </li></ul></ul><ul><ul><li>Improved sense of well-being because of improved sleep </li></ul></ul>