Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. CHAPTER 13 Central Nervous System Depressants and Muscle Relaxants

2 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. CNS Depressants Sedatives  Drugs that have an inhibitory effect on the CNS to the degree that they reduce:  Nervousness  Excitability  Irritability without causing sleep

3 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. CNS Depressants (cont’d) Hypnotics  Cause sleep  A sedative can become a hypnotic if it is given in large enough doses

4 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. CNS Depressants (cont’d) Sedative-hypnotics—dose dependent  At low doses, calm the CNS without inducing sleep  At high doses, calm the CNS to the point of causing sleep  Barbiturates  Benzodiazepines  Others

5 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Sleep  Normal sleep is cyclic and repetitive  A sleeping person is unaware of sensory stimuli within the immediate environment  Rapid eye movement (REM) sleep  Non-REM sleep  Sleep stages  REM rebound

6 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. CNS Depressants: Benzodiazepines  A commonly prescribed drug class  Favorable drug effect profiles, efficacy, and safety

7 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Benzodiazepines  Classified as either:  Sedative-hypnotic  Anxiolytic (medication that relieves anxiety)

8 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Benzodiazepines: Sedative-Hypnotic Types  Long-acting  estazolam (Prosom), flurazepam (Dalmane), lorazepam (Ativan), others  Short-acting  temazepam (Restoril), alprazolam (Xanax), triazolam (Halcion), others

9 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. CNS Depressants: Nonbenzodiazepine Hypnotics  Share many characteristics of benzodiazepines  Used to treat insomnia  Examples: zalepion (Sonata), zolpidem (Ambien), eszoplicone (Lunesta), and ramelteon (Rozerem)  Eszoplicone and extended-release zolpidem (Ambien CR) approved for long-term therapy

10 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. CNS Depressants: Nonbenzodiazepine Hypnotics  Ramelteon (Rozerem)  Does not cause CNS depression  No potential for abuse  No withdrawal signs and symptoms

11 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. 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

12 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Benzodiazepines: Drug Effects  Calming effect on the CNS  Useful in controlling agitation and anxiety  Reduce excessive sensory stimulation, inducing sleep  Induce skeletal muscle relaxation

13 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Benzodiazepines: Indications  Sedation  Sleep induction  Skeletal muscle relaxation  Anxiety relief  Treatment of alcohol withdrawal

14 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Benzodiazepines: Indications (cont’d)  Agitation  Depression  Epilepsy  Balanced anesthesia  Moderate/conscious sedation

15 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Benzodiazepines: Adverse Effects Mild and infrequent  Headache  Drowsiness  Dizziness  Vertigo  Lethargy  Fall hazard for elderly persons  “Hangover” effect/daytime sleepiness

16 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Benzodiazepines: Toxicity and Overdose  Somnolence  Confusion  Coma  Diminished reflexes  Do not cause hypotension and respiratory depression unless taken with other CNS depressants  Treatment symptomatic and supportive  Flumazenil as an antidote

17 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Benzodiazepines: Interactions  Other CNS depressants (alcohol, opioids)  Cimetidine  MAOIs  Herbal products: kava and valerian  Grapefruit juice alters drug absorption

18 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Herbal Products: Kava  Used to relieve anxiety, stress, and restlessness, and to promote sleep  May cause temporary yellow skin discoloration (extended, continued intake)  May cause visual disturbances  Potential interactions with alcohol, barbiturates, and psychoactive drugs  Contraindicated in liver disease, alcoholism, other conditions  Patient should not operate heavy machinery during use

19 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Herbal Products: Valerian  Used to relieve anxiety, restlessness, and sleep disorders  May cause CNS depression, hepatotoxicity, nausea, vomiting, anorexia, restlessness, insomnia  Many interactions, including with CNS depressants, MAOIs, phenytoin, warfarin, alcohol  Contraindicated in cardiac and liver disease  Patient should not operate heavy machinery during use

20 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Sedative-Hypnotics: Barbiturates  First introduced in 1903; were the standard drugs for insomnia and sedation  Habit forming; low therapeutic index  Only a handful commonly used today due in part to the safety and efficacy of benzodiazepines

21 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Therapeutic Index  Dosage range within which a drug is effective but above which it is rapidly toxic  Barbiturates have a very narrow therapeutic index

22 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Barbiturates: Mechanism of Action  Site of action  Brainstem (reticular formation)  By inhibiting GABA, nerve impulses traveling in the cerebral cortex are also inhibited

23 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Barbiturates: Drug Effects  Low doses: sedative effects  High doses: hypnotic effects (also lower respiratory rate)  Notorious enzyme inducers  Stimulate liver enzymes that cause metabolism or breakdown of many drugs  Result in shortened duration of action

24 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Barbiturates: Indications  Hypnotics  Sedatives  Anticonvulsants  Anesthesia for surgical procedures

25 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Barbiturates: Four Categories  Ultra short-acting  Anesthesia for short surgical procedures, other uses  Short-acting  Sedation/sleep induction and control of convulsive conditions  Intermediate-acting  Sedation/sleep induction and control of convulsive conditions  Long-acting  Sleep induction, epileptic seizure prophylaxis

26 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Barbiturates: Four Categories (cont’d)  Ultra short-acting  Mephohexital, thiopental  Short-acting  Pentobarbital, secobarbital  Intermediate-acting  Butabarbital  Long-acting  Phenobarbital, mephobarbital

27 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Barbiturates: Adverse Effects Body SystemAdverse Effects CNSDrowsiness, lethargy, vertigo, mental depression, others RespiratoryRespiratory depression, apnea, bronchospasms, cough

28 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Barbiturates: Adverse Effects (cont’d) Body SystemAdverse Effects GINausea, vomiting, diarrhea, constipation OtherAgranulocytosis, hypotension, Stevens- Johnson syndrome, others

29 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Barbiturates: Adverse Effects (cont’d)  Reduced REM sleep, resulting in:  Agitation  Inability to deal with normal stress

30 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Barbiturates: Toxicity and Overdose  Overdose frequently leads to respiratory depression and subsequent respiratory arrest  Overdose produces CNS depression (sleep to coma and death)  Can be therapeutic  Anesthesia induction  Uncontrollable seizures: “phenobarbital coma”

31 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Barbiturates: Toxicity and Overdose  Treatment of overdose  Symptomatic and supportive  Maintain adequate airway  Assisted ventilation/oxygen therapy  Fluids  Pressor support  Activated charcoal

32 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Barbiturates: Drug Interactions  Additive effects  Alcohol, antihistamines, benzodiazepines, opioids, tranquilizers  Inhibited metabolism  MAOIs will prolong effects of barbiturates  Increased metabolism  Reduces anticoagulant response, leading to possible clot formation

33 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Common Barbiturates  butabarbital (Butisol)  pentobarbital (Nembutol)  phenobarbital (Luminal)  secobarbital (Seconal)

34 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. 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  Act directly on skeletal muscle  Closely resemble GABA

35 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. 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

36 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Muscle Relaxants: Indications (cont’d)  dantrolene (Dantrium)  Malignant hyperthermia crisis

37 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Muscle Relaxants: Adverse Effects  Extension of effects on CNS and skeletal muscles  Euphoria  Lightheadedness  Dizziness  Drowsiness  Fatigue  Muscle weakness, others

38 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Common Muscle Relaxants  baclofen (Lioresal)  cyclobenzaprine (Flexeril)  dantrolene (Dantrium)  metaxalone (Skelaxin)  tizanidine (Zanaflex)  Others

39 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. CNS Depressants: Nursing Implications  Before beginning therapy, obtain 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

40 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Nursing Implications  Give hypnotics 30 to 60 minutes before bedtime for maximum effectiveness in inducing sleep (depends on drug’s onset)  Most benzodiazepines cause REM rebound and a tired feeling the next day; use with caution in the elderly  Instruct patients to avoid alcohol and other CNS depressants

41 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Nursing Implications (cont’d)  Check with physician before taking any other medications, including over-the-counter medications  Rebound insomnia may occur for a few nights after a 3- to 4-week regimen has been discontinued

42 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Nursing Implications (cont’d)  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 adverse effects

43 Mosby items and derived items © 2011, 2007, 2004 by Mosby, Inc., an affiliate of Elsevier Inc. Nursing Implications (cont’d)  Monitor for therapeutic effects  Increased ability to sleep at night  Fewer awakenings  Shorter sleep-induction time  Few adverse effects, such as “hangover” effects  Improved sense of well-being because of improved sleep For muscle relaxants:  Decreased spasticity, decreased rigidity