HESI 4 Complete Study Guide 2020 | HESI 4 Complete Study Guide _ Graded A

HESI 4 Complete Study Guide 2020 – University of Arizona Chapter 10 Analgesic Drugs Overview • Pain management priority of nursing care, should incorporate both nonpharmaceutical and pharmaceutical methods • Analgesic: medications that relieve pain but do not cause loss of consciousness • Focus on opioids and adjuvant drugs Pain management • Tailored to each pts. need • Requires ongoing assessment and assessment of effectiveness • Nociceptors: sensory pain nerve receptors o Mu receptors: in dorsal horn of spinal cord and play the most crucial role o Kappa and Delta receptors are less important but still involved • Nociception: sensation of pain • Pain perception is linked to a number of mu receptors (lots of receptors, less sensitive) o Pain threshold: physiologic level of stimulus to produce painful sensation ▪ Similar in most individuals but has some genetic variability o Pain tolerance: psychological amount of pain a patient can endure without interfering with normal function Pain Classifications • Origination of pain can call for different types of drugs: o Somatic: NSAIDS. Originates from skeletal muscles, ligaments and joints o Visceral: opioids. Originates from organs and smooth muscles o Superficial: opioids. Originates from skin and mucous membranes o Deep: depends on what it is that is causing pain ( use of NSAIDs or OPIODS) Originates from tissues below skin level • Classified by causing diseases/conditionso Vascular: migraine o Referred: visceral nerve fibers synapse at a level in spinal cord close to fibers supplying specific subcut. tissues in the body (gallbladder-cholecystitis referred to back and scapular area) o Neuropathic: damage to PNS or CNS nerve fibers or idiopathic o Phantom: area of body that has been removed o Cancer: pressure of tumor mass or hypoxia or side effects of tx. o Central: tumors, trauma, inflammation, or diseases affecting CNS Gate Theory on Pain • Tissue injury releases bradykinin, histamine, potassium, prostaglandins, serotonin. • These chemicals initiate impulses at distal end of sensory nerve fibers that are conducted to dorsal horn of spinal cord. • “Gates” located in dorsal horn regulate flow of incoming sensory nerve impulses • Gate controls amount of impulse that is carried up spinal cord to brain o Closing of gate affected by activation of A fibers and inhibit impulse conduction o Opening of gate affected by C-fibers that allow transmission and pain to be felt o Fibers controlled by brain so brain can keep gate closed or open • Enkephalins and endorphins o Neurotransmitters bind to opioid receptors and close the pain gate Treatment of pain in special situations • Patient controlled analgesia (PCA) o Patients self-medicate by pushing button on pump to deliver pain med o Patient must be cognitively aware to push button, decreasing risk of OD • Complex pain syndromes o Need holistic or multimodal approaches • Cancer o Patient comfort with little regard to addiction o Opioid tolerance typically requires higher dosing and increased chance of addiction • Treatment of acute pain in those who are addicted to opioids o Opioid tolerant: occurs in as little as 1 wk o Longer acting better choice o Breakthrough pain ( happens between doses) might require prn immediate release supplementation • Adjunctive agents o Assist in relieving pain while allowing use of smaller doses of opioidso Can reduce adverse effects associated with high dosing of opioids o Include NSAIDS, antidepressants, antiepileptics and corticosteroids o Commonly used in Neuropathic pain World Health Organization 3-step analgesic ladder • Used first: Nonopioids with or without adjuvants- • Second: Opioids with or without adjuvants • Third: Opioids for mod to severe pain with or without nonopioids or adjuvant meds o Give meds before pain is at its peak----easier to treat, harder to catch up, (Meds are given less frequent and decrease amount of dosages) o If pain is present for more than 12 hours a day, analgesia doses individualized and best given ATC o If using long acting opioids, might need prn short acting for breakthrough pain o Titration of pain meds might be needed to find best control o A patient rate pain level less than 4 on a scale of 1-10 considered effective most places All Opioids • Derived from opium poppy plant • 3 natural alkaloids from plant used for clinical use: morphine and codeine( pain relievers) and papaverine (muscle relaxer). • Synthetic alterations of 3 alkaloids result in 3 different classes of opioids o Morphine like drugs o Meperidine like drugs o Methadone like drugs Mechanism of Action • Agonists: bind to receptors in brain to cause analgesia • Partial agonist (agonist-antagonists or mixed): bind to pain receptor but causes weaker pain response o Not a first line analgesic except in OB to decrease risk to fetus • Antagonist : Binds to pain receptor but does not reduce pain signalso Competes with and reverses effects of agonist and agonist-antagonist drugs Indications • Surgery/Post-procedure: Fentanyl, sufetanil, alfentanil o Fentanyl in transdermal form used for chronic pain in opioid tolerant patients • Post-op and other acute pain o Morphine, hydromorphone, oxycodone • Oxycontin is a sustained-release form of oxycodone that last up to 12 hrs. o “Contin” means continuous release (prolonged duration) • Cough suppressant o Codeine or hydrocodone • Diarrhea Contraindications • Allergy and severe asthma • Be aware of confusion regarding allergies to opioids vs side effects • Use cautiously in resp insufficiency o High ICP, morbid obesity (r/t Obstructive Sleep Apnea), MG < paralytic ileus, pregnancy Adverse Effects • Euphoria, potential for abuse • Histamine release causes itching, rash, peripheral vasodilation • Peripheral vasodilation causes flushing and orthostatic hypotension • Naturally occurring (morphine) elicit most histamine release • CNS depression that can lead to respiratory depression • GI: N/V, constipation o Constipation more likely in non-ambulatory patients, slow peristalsis, increase h2o absorption in intestines causing constipation • Urinary retention • Anaphylaxis rare • Toxicity o Naloxone and naltrexone are antagonists and antidote to opioid OD o Opioid withdrawal ▪ Opioid drug is discontinued abruptly or antagonist administered ▪ Withdrawal from drugs with short half-life start 6-12 h and peak at 24-72 h▪ Withdrawal from drugs with long half-life start at 24 h or longer and are typically milder ▪ Can be seen after as little as two weeks of therapy ▪ Encourage gradual dosage reduction o Resp depression ▪ Stimulation ▪ Ventilatory assistance: bag and mask or possible ETT ▪ Might need redosing of antidote if long acting opioid on-board Opioid Agonist Drug Profile Codeine Sulfate • Schedule II; forms: PO Has a ceiling effect (increasing dose won’t increase response) • Commonly used as antitussive • Can be combined with acetaminophen for mild- moderate pain • AE: upset stomach, most people will say they are allergic, but it just upsets their stomach o No longer used in peds. and high degree of stomach upset Fentanyl • Schedule II; forms: IV, transdermal, PO • For Mod to severe pain • Transdermal: used for chronic pain, typically nonescalating pain in people who have some tolerance o 6-12 hours to achieve steady state with first application o Changed every 72 hours • IV: used in OR and ICU settings during mechanical ventilation Hydromorphone (Dilaudid) • Schedule II; forms: IV, IM o X7 more potent than morphine (impacts dosing amounts) • Exalgo: po delivery system that is ER to decrease abuse potential Meperidine (Demerol) (on NCLEX, know that is not used anymore) • Schedule II; forms: PO, IM • No longer commonly used r/t normeperidine metabolite accumulating in brain and causing seizures• Beware in older adults, long term analgesia and kidney disease • May be used in ED for migraines or immediate post-op for shivering Methadone Hydrocholride • Schedule II; forms: PO, Parenteral • Detoxification of opioid addicts • May also be used for chronic or cancer pain • Accumulates in liver, kidneys and brain which will slowly be released, allowing 24h dosing • Less difficult on kidneys since it is eliminated through the liver Morphine Sulfate • Schedule II; forms: PO, Parenteral, rectal • Used for Severe pain and has high abuse potential • MS Contin and Kadian : extended- release forms • Renal impairment can cause buildup of metabolites-not a good choice for those impaired Oxycodone hydrochloride • Schedule II; forms: PO • Combined with acetaminophen (Percocet), or aspirin (Percodan) • Available Immediate- release (oxyIR) and Sustained-release (oxycontin) • Hydrocodone similar but weaker. Combined with acetaminophen (Vicodin) Opioid Agonists- Antagonists Drug Profile • Bind to mu receptors and complete with other substances • Lower risk for misuse and dependence • Can cause withdrawal in opioid dependent • Used for short term pain control or those who have hx of opioid dependence • Buprenorphine, butorphanol, nalbuphine, pentazocine Opioid Antagonists Drug Profile Naloxone hydrochloride (Narcan) • No analgesia or CNS depression • Used as antidote for opioid causing respiratory depression• Primary adverse effect is opioid withdrawal syndrome due to over-reversal in opioid-tolerant pts. Nonopioid and Miscellaneous Analgesics • Acetaminophen (APAP, Tylenol) most widely used o Blocks peripheral pain impulses by inhibiting prostaglandin synthesis o Lowers body temp by acting on hypothalamus when febrile o NO anti-inflammatory properties o Not associated with CV or platelet or GI side effects o Contraindicated in allergy, severe liver disease, G6PD deficiency (genetic) o Adverse effects: skin disorders, N/V, dyscrasisas, nephrotoxicity, hepatotoxicity o Hepatotoxicity most serious and associated with OD o Limit dose to 4000mg/day (manufacturer limits 3000mg/day) o Potentially lethal when OD • Acute OD: • Can cause hepatic necrosis and/or hepatic nephrotoxicity • Possibly reversed with acetylcysteine which prevents hepatotoxic metabolites from forming Acetylcysteine- Works best if given within 10 h Smells like rotten eggs, likely to cause vomiting: redosing if vomiting occurs within 1 hour of dosing • Long term-OD • More likely to cause perm liver damage • Monitor serum levels no sooner than 4 hours after ingestion, if no serum level cannot be determining ( due to not knowing amount or when token) then the over dose will be assume toxic and treatment with acetylcysteine, take serum level and keep redosing every 1 hours until vomiting stops o Interactions • Alcohol ( if chronic alcohol abuser, limit to 2000mg/day) • Phenytoin, barbiturates, warfarin, isoniazid, rifampin, beta blockers, anticholinergics • Anything that causes CNS depression • All NSAIDS• Tramadol o Dual action: weak bond to mu opioid receptors and inhibits re-uptake of norepi and serotonin o Sched IV (last five years), PO o Rapidly absorbed and not affected by food o Excreted by kidneys o Adverse effects mimic opioids o Increased risk of serotonin syndrome if taken with antidepressants, (SSRIs, MOI, antileptics other seizures meds) • S/S of serotonin syndrome is that everything goes higher ( BP,HR, temp which causes fever, shivering, sweating, muscle rigidity) • Transdermal lidocaine o Postherpetic neuralgia, local pain relief o Up to 3 patches may be placed on large painful area o Not to be worn longer than 12 h to decrease risk of heart arrhythmias • No AE that are systemic • Capsaicin: topical pepper product, used for muscle, joint and nerve pain o Treatment of fibromyalgia Analgesic Assess, Implement, Edu. • Assess: full pain assessment, pain tools o Assess neuro and resp. system, GI status, VS • Non-opioids: Acetaminophen o Monitor for poisoning such as rapid weak pulse, dyspnea, cold clammy extremities, bleeding, loss of energy, fever, sore throat o Monitor liver enzyme studies o Educate about use of OTC combo products o If OD and giving acetylcysteine, mix with flavored drink NSAIDS: Assess age before giving ASA o Risk of ulcers with ASA o Children: risk of Reye’s syndrome Tramadol: not given if 75 y/o or older o May cause drowsiness, dizziness so fall risk • Opioids:o VS, resp function, presence of head injury, LOC, GI & GU function o Monitor liver and kidney o Use cautiously in people with neurologic disorders o Assess age for very young and old o RR less than 10 (sometimes 12) considered resp. depression and need to be reported o Naloxone (Narcan) must be available and possibly given o Urine OP must be at least 600 ml/24 h o Monitor pupils for pinpoint (might signify OD) o Give before pain hits peak to maximize effectiveness and re-evaluate after giving o Prefer to give oral first if no N/V, possibly give with food o Safety measures to decrease falls - - - - - - - - - - - - Continued