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NURS 203, Pharmacology I Dr. Nolan. Most common complaint leading people to seek healthcare Can be acute or chronic ◦ Acute – less than ~3 months duration.

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Presentation on theme: "NURS 203, Pharmacology I Dr. Nolan. Most common complaint leading people to seek healthcare Can be acute or chronic ◦ Acute – less than ~3 months duration."— Presentation transcript:

1 NURS 203, Pharmacology I Dr. Nolan

2 Most common complaint leading people to seek healthcare Can be acute or chronic ◦ Acute – less than ~3 months duration ◦ Chronic – 3 months or longer

3  ACUTE  CHRONIC (longer than 3 months)  CANCER PAIN  SOMATIC PAIN  VISCERAL PAIN  NEUROPATHIC PAIN

4 Cancer ◦ Can be acute or chronic Somatic ◦ Localized to a certain area (bone, muscle, skin…) ◦ Can be acute (injury) or chronic (arthritis) Visceral ◦ Not localized, harder to define ◦ Nociceptors in internal organs are stimulated (hepatitis, pancreatitis…) ◦ Dull, aching, cramping, deep pain

5  Neuropathic ◦ Perpheral pain receptors or nerves, damaged or dysfunctional ◦ Excessive excitability in these areas, leading to exaggerated pain response ◦ Diabetic neuropathy, herpes zoster (Shingles, post- herpetic neuralgia) ◦ Not as responsive to normal analgesics

6 Tissue damage stimulates peripheral pain receptors – nociceptors Signal transmitted to spinal cord (ascending pathway) – hypothalamus – cerebral cortex A-delta fibers : acute, “fast” pain C fibers : slow, poorly localized pain Descending pathway – inhibitory pathway, includes endogenous opioids, norepinephrine and serotonin to suppress nociceptive transmission of pain impulse via substance P

7 Neural pathways for pain. Neural pathways for pain.

8  Opioids  Non Opioids ◦ NSAIDs ◦ Tramadol ◦ Acetaminophen  Antidepressants, antiepileptics ◦ Neuropathic pain  CNS vasoconstrictors ◦ Migraine pain

9  Which of the following drugs does not have a “ceiling” dose? ◦ A) acetaminophen ◦ B) ibuprofen ◦ C) aspirin ◦ D) morphine ◦ E) all of the above have ceiling doses that should not be exceeded Review Question

10  Relieve moderate to severe pain by inhibiting pain signal transmission from periphery to brain.  Well absorbed with PO, IM, SQ administration.  Metabolized in liver, metabolites excreted in urine.  Liver or Renal impairment can interfere with metabolism or excretion.

11  CNS ◦ Analgesia ◦ CNS depression ◦ Respiratory depression ◦ Pupil constriction  GI ◦ Slows motility ◦ Constipation ◦ N/V ◦ Bowel and Biliary spasm

12  Potent analgesics for moderate to severe pain  Acute and chronic pain ◦ best for nociceptive pain ◦ Not generally effective for non-nociceptive pain (neuropathic)  Serious side effects  No ceiling dose  chronic use universally leads to tolerance, physical dependence, may lead to addiction  tolerance leads to high doses in patients treated long term with opioids that could kill opioid naïve patients

13 Stimulate Mu and Kappa receptors ◦ Mu  Analgesia, ↓ gastric motility, sedation, respiratory depression, euphoria, physical dependence ◦ Kappa  Analgesia, ↓ gastric motility, sedation Mixed agonist/antagonists stimulate one, antagonize the other Antagonists antagonize both (block opioids from binding to receptor or displace) naloxone

14 Binding to Mu and Kappa receptors slows the transmission of pain impulses between cells in the periphery, spine, and brain Stimulating Mu and Kappa receptors activates the endogenous analgesia system ◦ Endorphins, etc. act on receptors same as exogenous (narcotic) agents

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16 Analgesia Sedation, CNS depression (life threatening) Respiratory depression (life threatening) Constipation Euphoria Nausea/vomiting Dependence Tolerance Miosis

17  CNS ◦ Analgesia ◦ CNS depression ◦ Respiratory depression ◦ miosis  GI ◦ Slows motility ◦ Constipation ◦ N/V ◦ Bowel and Biliary spasm

18  Well absorbed orally, and via SQ, IM, and IV  Metabolized hepatically  Excreted via urine  Liver or renal disease can inhibit clearance or efficacy  T 1/2 can range from minutes (IV) to days (fentanyl patch)

19  Before, during, after surgery ◦ To provide pain relief, sedation, ↓anxiety  Acute and chronic pain control, outpatient ◦ there is limited data on the safety and efficacy of treating chronic pain with opioids ◦ significant safety concerns  Pain/anxiety reduction for various procedures

20  Respiratory depression, lung disease  Hepatic/renal dysfunction  Increased intracranial pressure  Allergy (true allergy)

21  Opioid agonist (primarily acts on Mu receptor)  Named after the Greek God of dreams, Morpheus  Prototype opioid analgesic  DEA Schedule II (DEA CII)  Given PO, SL, PR, TD, SC, IM, IV, IT, PCA pump

22  Maximal analgesia and resp depression within: ◦ min IV ◦ 30 min IM ◦ min SC ◦ 60 min orally (IR). ER forms are QD or BID  Duration is 5-7 hours (PO ER ~ hours)

23  T 1/2 is about 7 hours  Metabolites accumulate in pts with renal/hepatic dysfunction, must reduce dose  30% bound to plasma proteins, extensive first pass metabolism ◦ So PO doses considerably higher than Inj doses

24 moderate to severe pain procedure related anxiety/pain MI related pain Pulmonary edema why?

25 head trauma – increased intracranial pressure long acting agents with short acting procedures respiratory depression can manifest after procedure

26 Profound sedation/CNS depression Constipation, N/V at least 41% incidence of constipation with chronic opioids in 2000 study, 95% of patients interviewed by nurses in a hospital oncology unit reported constipation as the major side effect of their pain therapy Resp depression, decreased breath sounds ◦ Encourage deep breathing, coughing Hypotension Physical dependence Paradoxical CMS stimulation and insomnia

27  24 hour controlled release ◦ Kadian, Avinza  BID-TID controlled release ◦ MS Contin, Oramorph  Q4-6h immediate release ◦ MSIR  Liquid ◦ MS oral solution, 10mg/5ml, 20mg/5ml, 100mg/5ml (concentrated)  Embeda (morphine/naltrexone) ◦ naltrexone inactive unless crushed

28  Embeda, Kadian, Avinza caps can be opened and sprinkled immed. prior to oral admin. ◦ DON’T chew the pellets!  IM vs. SQ for repeated doses to reduce tissue irritation  Don’t administer IV too quickly to avoid excessive sedation and RR depression ◦ 2.5mg to 15mg over 5 minutes  PO vs parenteral doses  TYPICAL DOSE: ◦ ORAL 30mg Q4h ◦ IV/IM 5-10mg q4h

29  Breakthrough pain ◦ Continuous infusion or SR forms will need short acting bolus or tablets for breakthrough pain  HIGH ALERT ◦ periodically monitor RR, BP ◦ caution if RR<10  Placebo effect ◦ Explain the therapeutic effect to the patient ◦ Suggestions of efficacy are often very effective in increasing analgesia  Don’t let pain get severe ◦ opioids are more effective in maintaining analgesia if pain doesn’t become severe

30  Watch the concentration ◦ DON’T confuse 20mg/5mL with 20mg/mL ◦ 20mg/mL liquid should be given via oral syringe  Bowel function ◦ Bowel habits should be documented before beginning opioid therapy ◦ assess periodically, daily if constipation. ◦ Administer docusate and stimulant laxatives (senna, bisacodyl) on a regular basis if tx exceeds a few days  bulk forming may lead to impaction, especially in palliative care ◦ watch for confounding drugs (anticholinergics) and dehydration

31  Don’t crush, break, chew, or dissolve sustained release (SR), controlled release (CR), or extended release (ER) dosage forms! ◦ rapid release of entire day’s dose an result in opioid overdose

32  CII, Potent opioid agonist  Available as IV, patch, SL tablet & film  IM/IV  Used pre, during, post surgery ◦ analgesic supplement for general anesthesia  Same cautions apply as for morphine ◦ head trauma ◦ profound sedation, RR depression…  Dosed in micrograms (mcg), caution!

33  Patch ◦ Duragesic (fentanyl patch) for chronic pain in opioid tolerant pts ◦ NOT for post-op pain, intermittent pain, or short term pain ◦ 92% absorbed through skin ◦ Dosed every 72 hours  take about 20 hours for the serum conc to reach one half after removal of patch  steady state and maximal analgesia reached by end of second patch application ◦ Comes as mcg/hr patches (eg. 50mcg/hr)

34  transmucosal ◦ short acting, for breakthrough cancer pain in opioid tolerant pts (Actiq, Fentora)  opioid tolerant means equivalent of 60mg/day morphine ◦ Buccal film  about half absorbed through muscoa, the other half swallowed  swallowed fentanyl is ~20% bioavailable ◦ Transmucosal tablets, lozenge (lollipop), and nasal spray also available  these products are NOT interchangeable on a per dose basis ◦ Exercise extreme caution if children in the household!  rapidly fatal  watch for partially used discarded “pops”

35 Embeda (morphine/naltrexone) intended use is to prevent abuse combines microencapsulated naltrexone core to morphine sulfate beads inside capsule only crushing, chewing, or dissolving will release the naltrexone to attenuate the euphoric effects of the morphine very expensive compared to morphine sulfate

36 Oxycodone (OxyContin) – CII ◦ IR and CR dosage forms ◦ “Oxy’s” became a common street drug, selling for over $100 per tablet ◦ Can be combined with APAP (Percocet) or ASA (Percodan) Hydrocodone (Vicodin) – CIII ◦ Similar to codeine in use and efficacy ◦ Combined with APAP

37 Hydromorphone (Dilaudid, Exalgo) - CII ◦ PO, PR, SC, IM, IV ◦ More potent than morphine, ↑efficacy PO vs morphine Oxymorphone (Opana) ◦ Derivative of morphine, similar characteristics Methadone (Dolophine) ◦ Synthetic form of morphine ◦ longer DOA (T 1/2 30h +)

38 Propoxyphene (Darvon, Darvocet) - CIV ◦ Least effective opioid out there ◦ No more effective than APAP, but causes sedation and resp depression like other opiates ◦ Toxic metabolite (norpropoxyphene) can accumulate and cause arrhythmias, pulmonary edema, apnea, and CV events. ◦ Often used in suicides ◦ Should be avoided in kids, older adults ◦ Banned in Britain and many other countries but continues to be prescribed in U.S. ◦ UPDATE: FDA just asked for withdrawal of propoxyphene from US market

39  Proper administration of an ordered narcotic ◦ A) can lead to addiction ◦ B) should be done promptly to prevent increased pain and the need for larger doses ◦ C) would include holding the drug as long as possible until the patient really needs it ◦ D) should rely on the patient’s request for medication

40  Meperidine (Demerol) - CII ◦ Synthetic derivative of morphine ◦ Despite some opinions, meperidine has not shown any benefit beyond other opioids for biliary colic, pancreatitis, labor, or migraine. ◦ Does help with drug induced rigors, anesthesia related shivering ◦ Toxic metabolite, normeperidine, limits it’s use  Accumulates with chronic use (>2 days), renal dysfunction  Very long T 1/2, not reversible with naloxone  Causes seizures, hallucinations, agitation ◦ Naloxone will reverse effects of meperidine, leaving normeperidine unopposed – risk of seizures! ◦ Use > 2 days not appropriate

41  Meperidine (Demerol) - CII ◦ Drug interactions  serotonin syndrome  increased risk of MAO-I interactions and any serotonergic drug, including triptans  serotonin reuptake inhibition

42 Nucynta (tapentadol) CII MOA Opioid agonist (not as potent as morphine) Norepinephrine reuptake inhibitor (NRI) acts on decending pathway Dosing IR and ER forms available 600mg max daily dose. Why? Monitoring CNS/RR depression seizures, tachycardia, BP changes especially in patients taking antidepressants Side effects same as other opioids, but ~20% reduced incidence of GI S/E NOT totally reversed by naloxone

43 Tramadol (Ultram, Ultracet, Ryzolt) ◦ Not related to opioids chemically ◦ About as effective as Tyl#3 (codeine + APAP) ◦ MOA: binds to Mu receptor, SNRI ◦ Very little resp. depression, risk of dependence ◦ Well tolerated, good for older folks

44 MED for Selected Opioids Opioid Approximate Equianalgesic dose (oral & transdermal) * Morphine (reference)30mg Codeine200mg Fentanyl transdermal12.5mcg/hr Hydrocodone30mg Hydromorphone7.5mg MethadoneChronic: 4mg Oxycodone20mg Oxymorphone10mg

45 Block binding to opioid receptors, and can displace opioids bound there Used for quick reversal of opioid toxicity/overdose ◦ Reverses analgesia and CNS/resp. depression Naloxone (Narcan), naltrexone (ReVia, Vivitrol) ◦ Naloxone works within minutes of injection (SC, IM, IV) ◦ Short DOA (1-2h), may need to be repeated

46 For suspected narcotic OD ◦ Give IVP over sec ◦ 0.4mg – 2mg ◦ Repeat q 2-3 min if needed, up to total 10mg ◦ If no effect at 10mg, probably not narcotic OD ◦ No effect in the absence of opioids in system ◦ Caution if suspected chronic opioid user, will precipitate immediate withdrawal

47  Naloxone ◦ short acting competitive opioid antagonis ◦ given parenterally, only 2% bioavailable PO ◦ Used exclusively to reverse opioid intoxication  Naltrexone ◦ given PO (Revia) and IM (Vivitrol) to treat alcohol dependence (main use) and opioid dependence (not very effective)  Vivitrol - monthly IM injection  Revia – PO QD

48 Withdrawal unlike withdrawal of benzodiazepines and barbiturates, opioid withdrawal is not life threatening in otherwise neurologically and cardiovascularly healthy patients Stage I – drug craving, anxiety (~5-15 hrs) Stage II – yawning, perspiration, crying, rhinorrhea (~ 18 hrs) Stage III – mydriasis, continuation of Stage II, hyperreflexia, hot/cold flashes, cramping (16-24 hrs) Stage IV – continuation and worsening of Stage III, severe cramping, involuntary leg movements, diarrhea, HBP, ↑ body temp, ↑ RR, tachycardia, nausea (24 – 36hrs)

49 Withdrawal stage V – ↑ severity of earlier stages, fetal position, diarrhea, nausea, significant weight loss, leukocytosis, profuse sweating stage VI – appetite returns, bowel function normalizes, beginning of psychological withdrawal symptoms, ↑ sensitivity to pain, GI symptoms may see chronic withdrawal symptoms, both psychological and physical, after the post-acute withdrawal symptoms subside

50  Obtain baseline vital signs  Have naloxone available and know how to give it  Consider need for fixed schedule for patients experiencing chronic pain  Do not crush or break ER capsules/tablets

51 Assess pain relief ◦ Use pain scale Document pain relief Respiratory rate <12 BPM may be sign of overdose Baseline pupil size ◦ Miosis may be sign of toxicity Restlessness must be assessed and differentiated ◦ Is it hypoxia? ◦ Is it a need for more pain control? ◦ Is it paradoxical CNS stimulation?  (more common in women and older adults)

52  Encourage turning, coughing, and deep breathing at regular intervals  Be alert for orthostatic hypotension in ambulatory patients  Monitor urine output as morphine may dull the perception of a full bladder  Want pain free, but able to ambulate and take care of ADL’s. Too sedated, can’t do that…

53 No person should suffer pain needlessly Pain occurs when the patient says it does Pain should be relieved by whatever means required Doses of opioids should be titrated to maximal effectiveness Dependence rarely results from medications taken for physical pain

54 Withdrawal unlike withdrawal of benzodiazepines and barbiturates, opioid withdrawal is not life threatening in otherwise neurologically and cardiovascularly healthy patients Stage I – drug craving, anxiety (~5-15 hrs) Stage II – yawning, perspiration, crying, rhinorrhea (~ 18 hrs) Stage III – mydriasis, continuation of Stage II, hyperreflexia, hot/cold flashes, cramping (16-24 hrs) Stage IV – continuation and worsening of Stage III, severe cramping, involuntary leg movements, diarrhea, HBP, ↑ body temp, ↑ RR, tachycardia, nausea (24 – 36hrs)

55 Withdrawal stage V – ↑ severity of earlier stages, fetal position, diarrhea, nausea, significant weight loss, leukocytosis, profuse sweating stage VI – appetite returns, bowel function normalizes, beginning of psychological withdrawal symptoms, ↑ sensitivity to pain, GI symptoms may see chronic withdrawal symptoms, both psychological and physical, after the post-acute withdrawal symptoms subside

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58  You administer the third morphine dose of the day to a patient. Shortly thereafter, she’s found to be extremely lethargic with RR of 10. What course of action might be taken? ◦ A) None, she’ll probably be fine after the morphine wears off ◦ B) 0.4mg of IV naloxone and monitor ◦ C) 4mg of oral Narcan and monitor

59 USE THE LEAST POTENT DRUG THAT IS EFFECTIVE  Type of pain  combinations  non-pharmacologic interventions  Acute pain: PRN  Chronic pain: scheduled  Change the opioid if reduced efficacy  Ceiling vs. non-ceiling  Route  Short vs long acting, time release  Break through pain  PCA

60  NONINVASIVE ◦ Oral, rectal, transdermal  INVASIVE ◦ Subcutaneous, IM, IV, spinal infusion  When the route is changed, the dosage MUST be changed


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