Advanced Pharmacology – Pain Management – Flashcards
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Briefly review the physiology of pain and pain theory.
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Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage. Includes emotional and cognitive responses to both the sensation of pain and the underlying cause. Personal and subjective. When assessing pain, the most reliable method is to have the patient describe his/her experience.
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What are the two categories of pain?
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Nocieceptive Neuropathic
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What is nocieceptive pain?
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• Nociceptive Pain - results from injury to tissues (more common in cancer patients). o Somatic - results from injury to somatic tissues (bones, joints, muscles). Localized and sharp pain o Visceral - results from injury to visceral organs (small intestine). Vaguely localized, diffuse aching type of pain. Both types of pain respond well to opioid analgesics and nonopioids.
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What is neuropathic pain?
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Results from injury to peripheral nerves. Described as burning, shooting, jabbing, tearing, numb, dead, cold. Responds poorly to opioids, responds better to adjuvant analgesics. (TCA's, anticonvulsants (carbamazepine), and local anesthetics i.e. lidocaine
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What is the primary objective of the initial pain assessment?
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Characterize the pain and identify the cause. Helps to document the baseline pain status.
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What is the cornerstone of pain assessment?
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The patient's description of his/her pain.
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To do a thorough pain assessment, we must ask certain questions. What are they?
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o Onset and pattern - when did it start, how often, intensity increased? Decreased? Vary? o Location o Quality - what does it feel like? (sharp, dull, shooting, stabbing, etc) o Intensity - 0-10 scale o Modulating Factors - what makes it worse? Better? o Previous treatments - were they effective? If not, were they ever helpful? o Impact - how does the pain affect ability to function? Work, physically, socially, eating, sleeping, etc.
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Identify validated measures to assess outcomes of pain management
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Pain intensity scales (descriptive and numeric scales, FACES) are useful in assessing pain intensity as well as setting pain relief goals and evaluating treatment. Objective: Reduce pain to the agreed upon level and lower, if possible.
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What are the two primary approaches to pain management?
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1. Drug Therapy 2. Non-Drug Therapy
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List some of the drug pain therapy options.
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Drug Therapy - non-opioids like NSAIDs and acetaminophen Opioids - morphine, oxycodone, fentanyl Adjuvant analgesics - TCA's, lidocaine, anti-seizure meds, CNS stimulants, antihistamines, glucocorticoids, biophosphonates.
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List some of the non-drug pain therapy options.
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Non-Drug Therapy Invasive procedures - nerve blocks, neurosurgery, tumor surgery, radiation therapy Physical Interventions- Heat, cold, massage, exercise, acupuncture, TENS Psychosocial Interventions - Relaxation, imagery, cognitive distraction, peer support groups
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Briefly discuss criteria for analgesic selection.
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Selection is based on pain intensity and pain type. WHO designed a drug selection ladder. Common to combine an opioid with a non-opioid because the combo can be more effective than either drug alone.
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Discuss the use of World Health Organization (WHO) analgesic guidelines in the management of pain.
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3 step ladder. First step is for mild to moderate pain, consists of non-opioids (NSAIDS, acetaminophen). Second Step - more severe pain - adds opioids of moderate strength (oxycodone, hydromorphone) Third step - severe pain, uses most powerful opioids (morphine, fentanyl). Can use Adjuvants at any step - these are especially helpful in neuropathic pain
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What are some considerations in treating the elderrly for pain?
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Elderly - issues of special concern are the undertreatment of pain and increased risk of adverse effects, and heightened drug sensitivity. (decreased renal excretion, gastric ulceration, they have more disorders/physical ailments that may complicate dosing and drug-drug interactions)
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What are some considerations in treating young children for pain?
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Must tailor assessment to child's developmental level and personality. Self-reporting is preferred over behavioral observation. Verbal children tend to under-report pain. Behavioral observation in preverbal and non-verbal kids - crying, whining, groaning, facial expressions, muscle tension, inability to be consoled, protection of body areas, reduced activity.
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What is a migraine?
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Neurovascular disorder involving the dilation and inflammation of intracranial arteries.
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What 2 ways are antimigraine drugs used?
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1. Abortive 2. Prophylactic
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What is the goal of abortive therapy with a migraine?
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To eliminate the headache pain and associated n/v.
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What is the goal of prophylactic therapy with a migraine?
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To reduce the incidence and intensity of migraine attacks.
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What are the 2 types of drugs used for abortive therapy?
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1. Non-Specific analgesics (Aspirin-like drugs and opioids). 2. Migraine-Specific drugs - ergot alkaloids and triptans, DHE
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When would you use aspirin-like analgesics for a migraine?
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Mild to moderate intensity.
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When would you use opioid analgesics for a migraine?
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Reserved for severe migraines that have not responded to other drugs.
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What is a first line migraine-specific drug for abortive therapy with a migraine?
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Ergotamine
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What happens if you overdose on ergotamine?
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Can cause ergotism, a serious condition characterized by severe tissue ischemia secondary to generalized constriction of peripheral arteries.
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Can you get physically dependent on ergotamine?
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Yes, if taken routinely.
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Is it safe to take ergotamine during pregnancy?
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No. Can cause uterine contractions.
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What must ergotamine not be combined with and why?
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Potent inhibitors of CYP3A4 because of the risk for intense vasoconstriction and associated ischemia.
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Name a migraine-specific drug that is used for mild to moderate migraines.
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Triptans (sumatriptan).
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What is the MOA of triptans?
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Activate 5-HT receptors and thereby constrict intracranial blood vessels and suppress release of inflammatory peptides.
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All triptans are available in po form and have a slow onset. What 2 triptans are available NS, SQ, or both and have a rapid onset?
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Sumatriptan Zolmitriptan
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Triptans can cause coronary vasospasm and are therefore not recommended for a pt with what co-morbid illnesses?
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Ischemic Heart Disease Prior MI Uncontrolled HTN
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Can you combine triptans and/or with ergots?
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No, could cause excessive vasoconstriction.
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What psychoactive meds are contraindicated with triptans?
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SSRI's and SNRI's because it can cause serotonin syndrome.
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Who would prophylactic therapy be indicated for?
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Those with 2 or more attacks per month, especially severe attacks, or attacks that do not respond adequately to abortive agents.
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What other medications can be used for migraine prophylaxis?
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Depakote Propanolol Amitriptyline Topamax
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With what medication can you use to prevent menstrual-associated migraines?
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Estrogen
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What are the 3 main forms of headaches?
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1. Migraine 2. Cluster 3. Tension
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What are some precipitating factors to having a migraine?
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1. Anxiety 2. Fatigue 3. Stress 4. Menstruation 5. Alcohol 6. Weather changes 7. Tyramine containing foods.
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What are the two forms of migraines?
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Migraine with aura Migraine without aura
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What occurs with a migraine with an aura?
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Preceded by visual symptoms - flashes of light, blank area in field of vision, zigzag patterns.
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Of the 2 forms of migraine headaches, which one is more common?
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Migraine without aura which affects 70% of migrainers.
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What are the 5 groups of medications used for abortive therapy with migraines?
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Non-Specific Analgesics 1. NSAIDS - asa, naproxen, Excedrin migraine 2. Opioids Migraine Specific Drugs 1. Ergot Alkaloids 2. Triptans 3. DHE
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Use of abortive medications should be limited to 1-2x/week. Why?
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To avoid rebound headaches (MOH - medication overuse headache.)
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What is ergotism?
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Acute or chronic overdose of ergotamine that causes serious toxicity. Can cause ischemia secondary to constriction of peripheral arteries and arterioles; extremities become cold, pale, and numb, muscle pain develops, and gangrene may eventually result.
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What are the serotonin receptor agonists?
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Triptans
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What migraine-specific drug is approved for cluster headaches?
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Sumatriptan
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Can you take the migraine-specific meds while pregnant?
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No, they are both teratogenic. Ergot is a category X. Triptains are category C.
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What are some common adverse effects of the triptans?
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vertigo, malaise, fatigue, and tingling sensations. transient pain and redness may occur at sq site
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Is it safe to use Triptans with MAOI's?
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No, MAOI's can cause hepatic degradation of triptans, causing it's plasma level to rise resulting in toxicity.
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Describe a migraine headache
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MIGRAINE - moderate to severe throbbing pain that can be unilateral or bilateral. Typically lasts 4 hours to 3 days. Activity increases pain. Other symptoms include nausea, vomiting, photophobia, phonophobia, neck pain. Early morning onset. Preceded by Aura, more common in females, likely family history, substantial impact on daily life. Many precipitating factors including anxiety, fatigue, stress, menstruation, alcohol, weather changes and tyramine-containing foods.
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Describe a tension headache.
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bilateral headband like nonthrobbing mild to moderate pain. Lasts 30min-7 days. Typically no other associated symptoms. Usual onset is in the daytime, triggered by tension and anxiety. Slightly more common in females. Minimal impact on daily life.
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Describe a "cluster" headache.
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unilateral (behind the left or right eye) throbbing, or in the orbital-temporal area, sometimes piercing severe pain. Usually lasts 15 min to 2 hours. Headaches occur in clusters that typically consist of one or more headaches every day for 2-3 months, with a headache-free interval (months to years) between each cluster. Other symptoms include red conjunctiva, lacrimation, nasal congestion, rhinorrhea, ptosis, miosis - all on the same side as the headache. Onset is at night, typically no identifiable trigger, more common in males, usually a substantial impact on daily life - unlikely that there is a family history.
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Discuss the 3 phases of a migraine.
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1. Prodrome - fatigue, increased or decreased perception, irritability or withdrawal, food cravings, yawning, speech difficulties, hyperexcitability. 2. Aura - Visual disturbances,(flashes of light, a blank area in the field of vision, zigzag patterns) numbness/tingling, olfactory and auditory changes, dysphagia. Migraines without aura are most common. 3. Postdrome - Consists of lingering symptoms that resemble a hangover or flu-like symptoms. Though not universally present, postdromes generally follow migraines that are long in duration. Common symptoms of a postdrome include fatigue, poor concentration, irritability, queasy stomach, and tender muscles. Postdromes can usually be treated with rest or over-the-counter medications such as aspirin or naprosyn.
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What are the short term goals in dealing with a migraine?
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Short-Term Treatment Goals - RESCUE o Treat attacks rapidly, complete relief of pain and prevent recurrences with initial treatment o Restore pt's ability to function o Minimize use of recue medications o Optimize self care o Be cost effective o Have minimal or no adverse treatment effects
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What are the long term goals in treating a migraine?
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Long-Term Goals - PREVENTION o Reduce attack frequency, severity and associated disability o Improve quality of life o Prevent headache o Avoid headache medication escalation o Educate and enable patients to manage their disease.
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What is the MOA for sumatriptan?
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Sumatriptan MOA - selective cranial vasoconstriction, 5HT1B & 5HT1D receptor agonist - vasoconstricts & inhibits neurogenic inflammation
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What are the common AE's of sumatriptan?
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Adverse Effects - burning at injection site, warm, tingling sensation, neck/jaw tightness, flushing, tachycardia, dizziness, vertigo, drowsiness, fatigue. Bad taste with nasal spray. Chest heaviness, tightness or pressure.
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What is the MOA for Ergotamine?
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Ergotamine MOA - binds with 5HT receptor- vasoconstriction
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What are the common AE's of ergotamine?
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Side Effects - N/V, weakness in legs, myalgia, numbness, tingling in extremities, angina-like pain, rebound vasodilation, headache. Acute/chronic overdose. Physical dependence - rebound h/a. **Abortifacient
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What is the MOA for DHE?
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DHE - dihydroergotamine - MOA - alters transmission at serotonergic, dopaminergic and alph-adrenergic junctions. - drug of choice in refractory migraine or cluster headaches before the triptans. IV for status migrainosis, fewer side effects than ergotamine (no physical dependence) Diarrhea is biggest SE
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What is the biggest AE of DHE?
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Diarrhea.
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What are some considerations when treating children with a migraine?
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1. Use acetaminophen not aspirin Ages 6-11 maxalt or imitrex nasal sprays Adolescents triptans - axert, maxalt, imitrex, and zomeg (nasal sprays) DHE alone or with metoclopramide or promethazine (80-90% effective) Limited studies in prophylactic treatment of pedi migraines Drugs - propranolol, cyproheptadine, TCA's, Depakote, Topamax Consider a drug holiday if child has been headache free for 3 or more months
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What options are available for pregnant women with migraines?
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Tylenol??
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What are the two physiological causes of migraines?
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Inflammation Vasodilation
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Identify the major uses for narcotic analgesics
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Postoperative pain, Obstetric/labor delivery pain, MI, Head Injury, Cancer related pain, Chronic pain (non-cancerous types of chronic pain). Relieve severe pain, reduce anxiety before anesthesia, control coughing or diarrhea, temporarily maintain drug addiction (methadone), induce and maintain general anesthesia. Relieve SOB in pulmonary edema and heart failure.
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Identify the 3 major classifications and mechanism of action of narcotic analgesics.
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Pure Opioid Agonists - activate mu and kappa receptors - MU receptor agonist, mimic the actions of endogenous opioid peptides, primarily at the mu receptors. I. Strong opioid agonists - morphine is the prototype ii. Moderate to Strong opioid agonists - Codeine Mixed Agonist-antagonist Opioids - when given alone, produce analgesia. When given with a pure opioid agonist, it can antagonize analgesia. Antagonists at the mu receptors and agonists at the kappa receptors. Talwin (pentazocine) is the prototype. Pure Opioid Antagonists - act as antagonists at mu and kappa receptors. Principal use is reversal of respiratory and CNS depression caused by OD with opioid agonists. Naloxone (narcan) is the prototype.
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Describe the role of mu, kappa, & sigma receptors in pain control.
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MU receptors - when activated causes analgesia, respiratory depression, euphoria, and sedation, related to physical dependence. MU receptors are the most important of the three opioid receptors. Kappa Receptors - activation of kappa receptors causes analgesia and sedation Sigma Receptors -
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Discuss how a full pain agonist works.
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Activate Mu receptors and Kappa receptors. Relieve pain by mimicking the actions of endogenous opioid peptides. More effective against constant, dull pain. Produce analgesia, euphoria, sedation, respiratory depression, physical dependence, constipation, and other effects. Morphine is the prototype for the strong agonists. Codeine is prototype for the moderate to strong agonists. Other full agonists - mereridine, fentanyl, methadone, oxycodone. Schedule II.
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Describe how a partial agonist works.
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(Weak agonists) - also called Moderate to Strong Opioid Agonists. Codeine, oxycodone, hydrocodone, tramadol, tapentadol (Nucynta) - newer drug, activates MU receptors and blocks reuptake of Norepi. propoxyphene (off the market). The differences between these and full agonists (morphine) are primarily quantitative - they produce less analgesia and respiratory depression and have a somewhat lower potential for abuse. Codeine is Schedule II alone, Schedule III when combined with non-opioids. When formulated for cough suppression, schedule V.
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Describe how an agonist - antagonist works.
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Act as antagonists at mu receptors and agonists at kappa receptors (except for buprenorphine). Low potential for abuse, less respiratory depression, less euphoria and dependence, have a less powerful analgesic effect. Can precipitate withdrawal in a pt who is physically dependent on a pure opioid agonist. Pentazocine (Talwin) is the prototype. Indicated for mild to moderate pain. Produces analgesia, sedation, and respiratory depression, but the respiratory depression is limited. Increases cardiac workload. Can cause psychotomimetic reactions (anxiety, strange thoughts, hallucinations, nightmares) at high doses. Schedule IV . Drugs in this class include - Buprenorphine (suboxone), Butorphanol (stadol), Nalbuphine (Nubain), and Pentazocine (Talwin).
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Discuss the pharmacokinetics of opioid agonist.
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• Absorption - PO, IM, IV,SQ, epidural, and intrathecal. o IM, IV, and SQ - analgesia lasts 4-5 hours. Epidural and intrathecal up to 24 hours. PO depends on formulation (immediate relief 4-5 hours and extended release up to 24 hours) • Distribution - much of the drug is inactivated during first pass, PO doses much larger than parenteral route. Poor lipid solubility • Metabolism - Liver • Excretion - Kidneys
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Discuss the pharmacodynamics of opioid agonist.
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• Bind to opiate receptors • Dilate blood vessels • Suppress cough • Cause constipation/control diarrhea
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What is tolerance?:
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A state in which a larger dose is required to produce the same response that could formerly be produced with a smaller dose. Dosage must be increased to maintain analgesic effect.
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What is physical dependence?
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A state in which an abstinence syndrome will occur if drug use is abruptly stopped. The intensity and duration of the opioid abstinence syndrome depends on two factors - the half-life of the drug being used and the degree of physical dependence. Short half-lives (morphine) results in intense but brief abstinence syndrome symptoms. Opioids with long half-lives have less intense symptoms but more prolonged. The intensity of withdrawal symptoms parallels the degree of physical dependence. Rarely occurs when opioids are taken acutely to treat pain. Addictive behaviors rarely develop when physical dependence does occur. Cross-dependence exists among the pure opioid agonists.
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List some abstinence syndrome symptoms
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Initial reactions - yawning, rhinorrhea, and sweating. Onset occurs about 10 hours after final dose. Next comes the anorexia, irritability, tremor and gooseflesh. At its peak, the syndrome manifests as violent sneezing, weakness, nausea, vomiting, diarrhea, abdominal cramps, bone and muscle pain, muscle spasm and kicking movements. Withdrawal lasts about 7-10 days. Syndrome is very unpleasant but not dangerous as opposed to CNS depressants (barbituates and etoh) which can be lethal. Withdraw opioids slowly to avoid this syndrome.
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Describe addiction.
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A behavior pattern characterized by continued use of a psychoactive substance despite physical, psychologic, or social harm. Physical dependence is not required for addiction to occur, but it can contribute to addictive behavior - it is an underlying cause of addiction.
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Discuss the various routes of administration
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• ORAL - typically used for chronic, severe pain (cancer). Needs to be highly individualized. Morphine goes through extensive metablismon its first pass - po doses are higher than parenteral doses. Controlled release may be given q8-12 hours, and ER q 24 hrs. Do not use with ETOH, crush or chew. • IM & SQ- painful and unreliable, should be avoided. • IV - given slowly over 4-5 minutes. Rapid injection can cause severe adverse effects (hypotension, cardiac arrest, respiratory arrest). • Epidural and Intrathecal - spinal analgesia given in epidural route. Onset of analgesia is rapid and the duration prolonged up to 24 hours. Side effects are delayed respiratory and cardiac depression. Intrathecal doses are much smaller than epidural doses (about 1/10th). Dosing is highly individualized and to take into account age, body mass, physical status, history of opioid use, risk factors for respiratory depression and other medications being used before, during, and after surgery. • Other routes- lollipops,rectal,nasal spray, transdermal, sublingual, buccal film.
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List some of the adverse effects of opioid analgesia.
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Respiratory depression - most serious and most common cause of death. Constipation Orthostatic hypotension Urinary retention Emesis Elevated ICP Sedation Birth defects Neurotoxicity
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List some contraindications for using opiate analgesics.
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Closed Head Injury - already at risk for increased ICP and respiratory depression. Also morphine can cause side effects similar to diagnostic signs of head injury (n/v, miosis, mental clouding and sedation) • Shock • Respiratory Depression and Asthma • Decreased respiratory reserve - can further exacerbate and compromise respirations. • Undiagnosed Acute Abdominal conditions - can cause toxic megacolon or paralytic ileus in patients with inflammatory bowel disease. • Pregnancy - can cause physical dependence in the fetus resulting in signs of withdrawal day or so after delivery. • History of addiction to opiates • Renal and Hepatic disease - effects of these drugs may be intensified and prolonged in pts with liver impairment.
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Identify drugs which may interact with opioid analgesics and the risk to the patient.
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These medications mostly intensify the side effects of the opioids • CNS Depressants • Anticholinergic Drugs • Hypotensive Drugs • Monoamine Oxidase Inhibitors • Agonist-Antagonist Opioids • Opioid Antagonists • Neuromuscular blocking agents • Loop Diuretics • Antipsychotics & Antidepressants
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Discuss Embeda - new long acting opioid - what is unique about its formulation?
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• Morphine + Naltrexone extended release • Taken every 12-24 hours. • Naltrexone has NO effect • If crushed or chewed, reverses the subjective and analgesic effects of morphine by competitively binding at mu-opioid receptors.
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Discuss the uses of mixed opioid agonists-antagonists for pain relief.
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• Relief of moderate to severe pain • Act as kappa receptor agonists and mu receptor antagonists • Low potential of abuse • Less respiratory depression - does cause some resp. depression, but it is limited • Less powerful analgesic effects • Can precipitate withdrawal if given to a pt who is physically dependent on a pure opioid agonist • Can treat overdoses with naloxone
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List the four drugs available in the opioid agonist-antagonist class.
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o Pentazocine (Talwin) protype - limited resp. depression, little to no euphoria, can produce psychotomimetic effects in high doses (anxiety, strange thoughts, nightmares, hallucinations). Increases cardiac workload. Physical dependence can occur, but withdrawal symptoms are mild o Nalbuphine (Nubain) - at low doses has analgesic actions equal to morphine, as dosage increases, a ceiling to analgesia is reached. Dependence can occur, withdrawal symptoms are more severe than pentazocine, but less severe than with morphine. Do not use during labor/delivery o Butorphanol (Stadol) - psychotomimetic reactions are rare, increases cardiac work, mild physical dependence and withdrawal o Buprenorphine (Buprenex, Butrans, Subutex, Suboxone) -
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Discuss the kinetics, dynamics, adverse reactions and interactions associated with mixed agonists-antagonists.
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• Routes are Oral, IV, IM and SQ • Maximal pain relief is generally lower than with pure opioid agonists • Have ceiling to respiratory depression • Cause little euphoria, thus abuse potential is low • Increase cardiac workload - don't use in MI • Can precipitate abstinence syndrome in pts who are physically dependent on opioid agonists • Adverse effects are similar to the opioid agonists (morphine)
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Discuss the use of adjuvants in the management of pain. (Table 29-5)
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• Used to complement the effects of opioids • Used in combination with opioids, not as a substitute • Can enhance analgesia from opioids • Help manage concurrent symptoms that exacerbate pain • Treat side effects caused by opioids • Especially useful in Neuropathic Pain • Pain relief is limited and less predictable and develops slowly
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Name some non-opiate drugs that can be used for pain but developed for something else.
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• Were developed for other uses than pain control • TCA's (amitryiptyline) - other antidepressants (bupropion, duloxetine, venlafaxine) • Antiseizure Drugs (carbamazepine) - effective in Lancinating pain (sharp, darting pain) • Gabapentin - effective and less SE's than carbamazepine • Local Anesthetics/antidysrhythics - Lidocaine and Mexiletine - 2nd line agents for neuropathic pain • CNS Stimulants - dextroamphetamine and methylphenidate • Antihistaimines - hydroxyzine - increase sedation and reduce anxiety • Glucocorticoids - reduce cerebral and spinal edema, improve appetite, improve sense of well-being • Biophosphonates - etidronate and pamidronate - can help reduce bone pain
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List some non-drug therapies used as adjuvant pain reliever.
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• Neurolytic Nerve Block • Neurosurgery • Tumor Surgery • Radiation Therapy
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List some Physical and Psychosocial Interventions for pain relief.
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• Heat, cold, massage, exercise, acupuncture, TENS • Relaxation and imagery, cognitive distraction, peer support groups.
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What is the role of opioid antagonists?
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• Block the effects of opioid agonists. • Principal uses are treatment of opioid overdose • Relief of opioid induced constipation • Reversal of postoperative opioid effects (respiratory depression, ileus) • Management of opioid addiction
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What is the major difference between Naloxone and Naltrexone?
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NALOXONE - acts as a competitive antagonist at opioid receptors, thereby blocking opioid actions. Reverse most effects of the opioid agonists, including respiratory depression, coma, and analgesia. Can also reverse the agonist-antagonists opioids. Can be used to reverse postop and labor/delivery respiratory and CNS depression, both in adults and the newborn. Can be used when uncertain of source of OD (etoh? Barbituates?) Will not cause harm if it is not an opioid. Can be given IV, IM, or SQ. NALTREXONE - is given PO or IM. Used for opioid and alcohol abuse. Prevents euphoria if pt uses an opioid, but not cravings. Less successful than methadone for addictions. It is a pure opioid antagonist.
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How does an antagonist such as naloxone work with an agonist and a partial agonist?
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It can reverse toxicity from agonist-antagonist opioids (pentazocine, nalbuphine), but the doses required may be higher than those needed to reverse poisoning by pure agonists.
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Discuss role of methylnaltrexone (Relistor) it treating opioid induced constipation? What other means may be used?
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• Methylnaltrexone - a selective mu opioid antagonist indicated for opioid-induced constipation in patients with end stage illness (cancer, AIDs, heart failure, emphysema), who are taking opioids continuously to relive pain and have not responded to standard laxative therapy. • Blocks the mu receptors in the GI tract, contains a methyl group so does not readily cross membranes including the BBB, thus CNS opioid receptors are not blocked. • Does not decrease analgesia or cause withdrawals like narcan/naloxone
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What are the 3 major classes of opioid receptors?
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Mu Kappa Delta
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Morphine and other pure opioid agonists relieve pain at what receptors?
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Primarily mu, partly kappa
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Infants have poorly developed BBB's. Therefore, how will you adjust their dosage?
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Need smaller doses.
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With prolonged use, tolerance develops to most adverse effects except 2. What are they?
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Constipation Miosis
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Patients taking opioids should avoid anticholinergic drugs. Why?
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Because they exacerbate constipation and urinary retention.
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What is the triad of symptoms of opioid overdose
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Respiratory depression Coma Pinpoint pupils
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Respiratory depression is common with opioids. Is this true with agonist-antagonists as well?
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There is a ceiling with respiratory depression with agonist-antagonists.
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Is it best to schedule opioid doses or prn?
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Best to schedule administration of opioids for pain and prn doses for breakthrough pain.
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What happens if you use parenteral opioids during delivery?
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Can suppress uterine contractions and cause respiratory depression in the neonate.
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Can cancer pain be relieved all the time?
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90% of the time, pain can be relieved in cancer patients.
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What are the common barriers to proper pain relief?
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Doctors don't order enough. Nurses don't give enough Until recently, healthcare system put little priority on it. First two, due to fear of addiction.
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Is behavioral observation, a good way to assess pain?
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No. The patient self-report is much more reliable.
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Is it ever a good idea to combine an opiate and a non-opiate pain reliever?
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Yes, it's actually more effective than either on it's own.
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NSAIDS produce their effect by inhibiting cyclooxygenase COX). Name the two basic forms.
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Cox-1 Cox-2
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What are the common adverse effects of NSAIDS?
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GI injury, acute renal failure, and bleeding. Also, all NSAIDS, except ASA pose a risk of thrombotic events.
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COX-2 inhibitors cause less GI injury. But, they cause a greaert risk for what?
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Thrombotic events. Should not be used long-term.
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Tylenol is like the NSAIDS in that it relieves pain. Name3 ways that it is different.
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1. Does not suppress inflammation. 2. Does not Inhibit platelet aggregation 3. Does not promote gastric ulceration 4. Does not cause renal failure
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What happens if you combine Tylenol and alcohol?
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Potentially can cause fatal liver failure.
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Opiates are effective against nociceptive pain. What about neuropathic pain?
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Not particularly useful. Effect is limited.
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The opioids fall into what 2 major groups?
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1. Pure opioid agonist (morphine) 2. Opioid agonist-antagonist (butorphanol)
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What is the preferred route of administration for opiates?
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Oral is best. IM is painful and should be avoided. Transdermal is a good alternative to po.
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What do you use an equianalgesia table for?
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Switching from one opioid to another.
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Is addiction to opiates common in people taking it for pain?
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No., in fact, it's very rare.
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What is the most dangerous SE of opioids?
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Respiratory depression. Fortunately, significant resp depression is rare.
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Why is it important to limit the use of meperidine to a couple of days?
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Because with longer use, you can accumulate a toxic metabolite.
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Invasive therapies (nerve blocks, surgery, radiation) can be used to treat pain. When should you use them?
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As a last resort. When nothing else has helped.
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Why are elderly more sensitive to opiates than younger people?
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Because of the decrease in hepatic metabolism and renal excretion.
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Do the elderly typically get their pain relieved?
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No. Under treatment of pain in the elderly is all too common.
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What is the most reliable way to assess pain in children older than 4 yo?
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Self-reporting is best. Can also consider behavioral observation but should be supplemental, not primary.
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How do you achieve pain relief in the opioid abuser?
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They sometimes need pain relief like everyone else. If their pain justifies opiate, they should receive opiate pain relievers.
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What is the action of ASA?
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1. Inhibits COX-1 & COX-2 2. Inhibits prostaglandin and thromboxane synthesis 3. Prevents platelet aggregation 4. Prevents vasoconstriction
question
Name 3 new NSAIDS.
answer
1. Cambia - acute migraine 2. Zipsor - mild to moderate pain >18 yo, liquid filled capsule 3. Caldolor - injectable ibuprofen, hospital only
question
What is the prototype for Cox-2 inhibitors?
answer
Celebrex
question
What are some contraindications for Celebrex?
answer
1. Hypersensitivity to drug - duh! 2. ASA or NSAID hypersensitivity 3. Sulfa hypersensitivity
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What are some general prescribing pearls when prescribing NSAIDS?
answer
1. Give with food. 2. DC before surgery 3. Observe for bleeding, tinnitus 4. Don't mix with ASA
question
What is the action of Tylenol?
answer
Interferes with prostaglandin synthesis