Opioid Analgesic Agents

1. Opioid Analgesic Agents

2. Analgesics • Medications that relieve pain without causing loss of consciousness • Painkillers

3. Classification of Pain By Source Vascular pain • Possibly originates from vascular or perivascular tissues Neuropathic pain • Results from injury to peripheral nerve fibers or damage to the CNS Superficial pain • Originates from skin or mucous membranes

4. Pain Transmission Tissue injury causes the release of: • Bradykinin • Histamine • Potassium • Prostaglandins • Serotonin These substances stimulate nerve endings, starting the pain process.

5. Pain Transmission • These pain fibers enter the spinal cord and travel up to the brain. • The point of spinal cord entry is the DORSAL HORN. • The DORSAL HORN is the location of the “GATE.”

6. Pain Transmission • This gate regulates the flow of sensory impulses to the brain. • Closing the gate stops the impulses. • If no impulses are transmitted to higher centers in the brain, there is NO pain perception.

7. Pain Transmission • Body has endogenous neurotransmitters • Enkephalins • Endorphins • Produced by body to fight pain • Bind to opioid receptors • Inhibit transmission of pain by closing gate

8. Pain Transmission Rubbing a painful area with massage or liniment stimulates large sensory fibers • Result: • GATE closed, recognition of pain REDUCED • Same pathway used by opiates

9. Opioid Analgesics • Pain relievers that contain opium, derived from the opium poppy or • chemically related to opium Narcotics: very strong pain relievers

10. Opioid Analgesics • codeine sulfate • meperidine HCl (Demerol) • methadone HCl (Dolophine) • morphine sulfate • propoxyphene HCl

11. Opioid Analgesics: Mechanism of Action • Bind to receptors on inhibitory fibers, stimulating them • Prevent stimulation of the GATE • Prevent pain impulse transmission to the brain

12. Opioid Analgesics: Therapeutic Uses Main use: to alleviate moderate to severe pain • Opioids are also used for: • Cough center suppression • Treatment of constipation

13. Opioid Analgesics: Side Effects • Euphoria • Nausea and vomiting • Respiratory depression • Urinary retention • Diaphoresis and flushing • Pupil constriction (miosis) • Constipation

14. Opiate Antagonists naloxone (Narcan) naltrexone (Revia) • Opiate antagonists • Bind to opiate receptors and prevent a response Used for complete or partial reversal of opioid-induced respiratory depression

15. Opiates: Opioid Tolerance • A common physiologic result of chronic opioid treatment • Result: larger dose of opioids are required to maintain the same level of analgesia

16. Opiates: Physical Dependence • The physiologic adaptation of the body to the presence of an opioid

17. Opiates: Psychological Dependence (addiction) • A pattern of compulsive drug use characterized by a continued craving for an opioid and the need to use the opioid for effects other than pain relief

18. Opiates • Opioid tolerance and physical dependence are expected with long-term opioid treatment and should not be confused with psychological dependence (addiction).

19. Opiates • Misunderstanding of these terms leads to ineffective pain management and contributes to the problem of undertreatment.

20. Opiates • Physical dependence on opioids is seen when the opioid is abruptly discontinued or when an opioid antagonist is administered. • Narcotic withdrawal • Opioid abstinence syndrome

21. Opiates Narcotic Withdrawal Opioid Abstinence Syndrome • Manifested as: • anxiety, irritability, chills and hot flashes, joint pain, lacrimation, rhinorrhea, diaphoresis, nausea, vomiting, abdominal cramps, diarrhea

22. Opioid Analgesics: 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. • Assess for potential contraindications and drug interactions.

23. Opioid Analgesics: Nursing Implications • Perform a thorough pain assessment, including nature and type of pain, precipitating and relieving factors, remedies, and other pain treatments. • Assessment of pain is now being considered a “fifth vital sign.”

24. Opioid Analgesics: Nursing Implications • Be sure to medicate patients before the pain becomes severe as to provide adequate analgesia and pain control. • Pain management includes pharmacologic and nonpharmacologic approaches. Be sure to include other interventions as indicated.

25. Opioid Analgesics: Nursing Implications • Oral forms should be taken with food to minimize gastric upset. • Ensure safety measures, such as keeping side rails up, to prevent injury. • Withhold dose and contact physician if there is a decline in the patient’s condition or if VS are abnormal—especially if respiratory rate is below 12 breaths/minute.

26. Opioid Analgesics: Nursing Implications • Follow proper administration guidelines for IM injections, including site rotation. • Follow proper guidelines for IV administration, including dilution, rate of administration, and so forth. CHECK DOSAGES CAREFULLY

27. Opioid Analgesics: Nursing Implications • Constipation is a common side effect and may be prevented with adequate fluid and fiber intake. • Instruct patients to follow directions for administration carefully, and to keep a record of their pain experience and response to treatments. • Patients should be instructed to change positions slowly to prevent possible orthostatic hypotension.

28. Opioid Analgesics: Nursing Implications • Patients should not take other medications or OTC preparations without checking with their physician. • Instruct patients to notify physician for signs of allergic reaction or adverse effects.

29. Opioid Analgesics: Nursing Implications Monitor for side effects: • Should VS change, patient’s condition decline, or pain continue, contact physician immediately. • Respiratory depression may be manifested by respiratory rate of less than 12/min, dyspnea, diminished breath sounds, or shallow breathing.

30. Opioid Analgesics: Nursing Implications Monitor for therapeutic effects: • Decreased complaints of pain • Increased periods of comfort • With improved activities of daily living, appetite, and sense of well-being

31. Central Nervous System Depressants

32. CNS Depressants Sedatives • Drugs that have an inhibitory effect on the CNS to the degree that they reduce: • Nervousness • Excitability • Irritability • without causing sleep

33. CNS Depressants Hypnotics • Calm or soothe the CNS to the point that they cause sleep

34. CNS Depressants 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

35. Sedative-Hypnotics: Barbiturates Barbiturates have a very narrow therapeutic index. Therapeutic Index • Dosage range within which the drug is effective but above which is rapidly toxic.

36. Sedative-Hypnotics: Barbiturates Mechanism of Action • Site of action: • Brain stem (reticular formation) • Cerebral cortex • By inhibiting GABA, nerve impulses traveling in the cerebral cortex are also inhibited.

37. Sedative-Hypnotics: Barbiturates Drug Effects • Low doses: Sedative effects • High doses: Hypnotic effects (also lowers respiratory rate) Notorious enzyme inducers

38. Sedative-Hypnotics: Barbiturates Therapeutic Uses • Hypnotics • Sedatives • Anticonvulsants • Surgical procedures

39. Sedative-Hypnotics: Barbiturates Side Effects Body System Effects CNS Drowsiness, lethargy, vertigo mental depression, coma Respiratory Respiratory depression, apnea, bronchospasms, cough

40. Sedative-Hypnotics: Barbiturates Side Effects Body System Effects GI Nausea, vomiting, diarrhea Other Agranulocytosis, vasodilation, hypotension, Stevens-Johnson syndrome

41. Sedative-Hypnotics: Barbiturates Toxicology • Overdose frequently leads to respiratory depression, and subsequently, respiratory arrest. • Can be therapeutic: • Anesthesia induction • Uncontrollable seizures: “phenobarbital coma”

42. CNS Depressants: Benzodiazepines Mechanism of Action • Depress CNS activity • Affect hypothalamic, thalamic, and limbic systems of the brain • Benzodiazepine receptors

43. CNS Depressants: Benzodiazepines Drug Effects • Calming effect on the CNS • Useful in controlling agitation and anxiety

44. 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.

45. CNS Depressants: 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.

46. CNS Depressants: 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. • Abruptly stopping these medications, especially barbiturates, may cause rebound insomnia.

47. CNS Depressants: Nursing Implications • Safety is important • Keep side rails up • Do not permit smoking • Assist patient with ambulation (especially the elderly) • Keep call light within reach • Monitor for side effects

48. CNS Depressants: 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