N323 - Week 6 (Pathophysiology Review & Drugs for the Control of Pain)

Non Pharmacological Therapies (7)

Acupuncture

-Biofeedback (mind, body technique used to regulate HR & etc)

-Massage

-Heat or cold

-Meditation or prayer

-Relaxation therapy

-Art or music therapy

Hot or Cold

Hot: Causes vasodilation, opens permeability -> allows WBCs to go & provide support

-Cold: Closes vasoconstriction, closes permeability -> prevents inflammatory agents from getting to the site

Nociception

Perception of pain

Nociceptors

free nerve endings in skin, muscles, joints, arteries & the viscera that respond to chemical, mechanical, & thermal stimuli

-can detect a wide range of stimuli

2 Types of Nociceptors

A-delta myelinated fibers

-Unmyelinated C polymodal fibers

A-delta myelinated fibers

transmit fast, sharp pain

-felt on skin surface

-EX: burn, pin, prick (pull hand away fast)

(Myelinated -> have a covering)

Unmyelinated C polymodal fibers

smaller fibers that transmit dull, aching, burning sensations

-for poorly localized, constant pain

-located on bone, tendons, muscles, organs

Pain threshold

Point at which a stimulus is perceived as pain

Perceptual dominance

Pain at one location may cause an increase in the threshold in another location

Pain tolerance

Duration of time or the intensity of pain that a person will endure before initiation of pain responses

Types of pain

acute

-chronic

-nociceptive

-neuropathic

acute (3)

newer onset, organ or tissue damage (both A & C fibers involved) -> alerts us that something is harmful & mobilizes us to stay away

-caused by stimuli (if stimuli is not present, pain should eventually go away) -> can be up to 3 mnths

-break-through pain (BTP) -> opioid use related

chronic (4)

3-6 mnths duration or lasting beyond expected time of healing

-pain does NOT decrease even when stimuli is not present

-may be part of disease process or result of disease treatment

-EX: cancer related pain vs not cancer related pain

Nociceptive pain

Type of acute pain

-may be somatic or visceral

Somatic (3)

injury to tissue (skin), localized

-both A & C fibers

-EX: abrasions, lacerations, muscle strains...

Visceral (4)

felt by stretch receptors

-poorly localized, dull, deep, achy, cramping, throbbing

-more transmitted through C fibers

-EX: injury to organs, linings of body cavities, may cause referred pain

Referred Pain

pain that is felt in a location other than where the pain originates

-EX: heart attack -> may have pain in left arm

-EX: kidney pain -> flank pain

Neuropathic (3)

abnormal neuronal activity secondary to disease, injury or dysfunction of the NS-> leads to abnormal processing of pain (amplified pain)

-described as "burning, shooting, tingling"

-usually not a visible injury or inflammation (hard to treat)

EX of Central Neuropathic Pain (2)

Post-stroke

-spinal cord injuries

EX of Peripheral Neuropathic Pain

post-herpetic neuralgia : severe nerve pain associated w/ shingles (can also cause rash)

Treatment modalities for pain (6)

pharmacologic, physical medicine, behavioral medicine, neuromodulation, interventional, & surgical approaches

Opioid Receptors

Main pain receptors

2 Main types of Opioid receptors

μu (MOP): located throughout CNS

Kappa (KOP): located in diencephalon, brain stem, spinal cord

Other Opioid Receptors (2)

Delta (DOP): Brain, spinal cord, digestive tract

Nociceptin Orphanin (NOP): Located on afferent fibers (can induce pain; but regulates HR, muscle contractility, immune system & etc.)

Types of Opioids (3)

Pure opioid agonist

Mixed opioid agonists

Opioid antagonists

Pure opioid agonist

bind to both μu & Kappa

-most opioids are pure opioid agonist

Mixed Opioid agonists

bind to one, but blocks the other

-Most common: Buprenorphine (binds to μu, blocks kappa)

Opioid Antagonists

blocks both, very competitive

-Most common: Naloxone

Drug Schedules

Schedule I: Most potential for abuse & dependence (not prescribed)

Schedule II & III can be given

Non-Opioid Agents (4)

acetaminophen (Tylenol)

Aspirin (ASA)... NSAID

Ibuprofen (Motrin).. NSAID

Naproxen (Naprosyn).. NSAID

Acetaminophen (APAP) (Tyelonol)

Routes:

MOA:

Classification:

Primary use:

Adverse Effects:

Nursing Considerations: (3)

Routes: PO, PR (per rectum), IV

MOA: decreasing prostaglandin synthesis in CNS (prostaglandin causes perception of pain & fever)

Classification: Antipyretic

Primary use: Mild to moderate nociceptive pain; fever reducer

Adverse Effects: Mild

Nursing Considerations:

-A dose of >4g can be associated w/ liver fxn abnormalities

-Ingestion of 15g may be fatal due to severe hepatotoxicity w/ centrilobular necrosis (cell death in liver), sometimes associated w/ acute renal tubular necrosis

-Might be 'hidden' in other OTC cold & flu agents and in narcotics

Aspirin, Aspirin enteric coated, Bayer (ASA).. NSAID

MOA:

Classification:

Adverse Effects: (3)

Nursing Considerations: (4)

MOA: Irreversible inhibition of COX-1 & COX-2 enzymes. Acetylation blocks entry of arachidonic acid to the active site of the enzymes

Classification: analgesic, anti-inflammatory/ antipyretic, salicylate

Adverse Effects: thrombocytopenia, bleeding, gastric ulcers

Nursing Considerations:

-Caution in pts w/ known GI-peptic ulcer disease

-Monitor closely for acute bleeding

-Educate pt to not use with NSAIDs often

-Has cardioprotective dosing (81mg daily)

-Not for pediatric pts -> can cause Reyes syndrome (30-40% morality)

Ibuprofen (Motrin, Advil)... NSAID

MOA:

Classification:

Adverse Effects:

Nursing Considerations: (4)

MOA: decreasing prostaglandin synthesis through blockage of COX enzyme

Classification: Analgesic, NSAID, Antipyretic

Adverse Effects: ulcerations, CV thrombotic

Nursing Considerations:

-Avoid use in advanced renal disease & failure (CrCL< 30ml/min)

-May prolong bleeding time (not recommended for post op pts)

-Educate caution w/ daily use greater than 2 wks

-Not for use in 1st-2nd trimester of pregnancy (closes duct for fetal circulation)

Naproxen (Naprosyn), Aleve-OTC... NSAID

MOA:

Classification:

Adverse Effects:

Nursing Considerations: (3)

MOA: Reversibly inhibits COX 1 & 2 enzymes -> less prostaglandins

Classification: analgesic, NSAID, antipyretic

Adverse Effects: GI bleeding, ulcers

Nursing Considerations:

-Caution in advanced renal disease & failure, highly protein bound

-May prolong bleeding time

-Educate caution w/ daily use greater than 2 wks

Opioids (8)

-tramadol (Ultram).. Centrally Acting -Opioid Analgesic

-morphine (MS Contin)

-hydromorphone (Dilaudid)

-fentanyl (Duragesic, Sublimaze, Fentora, Antiq)

-hydrocodone w/ acetaminophen (Lortab, Norco, Vicodin)

-codeine (Tylenol #3 & #4)

-buprenorphine (Buprenex, Butrans)... Mixed Opioid agonist

-Naloxone (Narcan).. Opioid Antagonist

Tramadol (Ultram) PO

MOA:

Primary use:

Classification:

Adverse Effects: (4)

Nursing Considerations: (5)

MOA: weak opioid activity - binds to μu receptors in the CNS causing inhibition of ascending pain pathways; also inhibits the reuptake of norepinephrine & serotonin

Primary use: as centrally acting analgesic (less intense)

Classification: Opioid analgesic

Adverse effects: GI upset, constipation, dizziness, lethargy

Nursing considerations:

-extreme caution for use w/ bleeding disorders

-extreme caution in severe renal or hepatic disease

-monitor renal & liver fxn while on this therapy

-avoid alcohol w/ use of morphine containing products

-close monitoring of bowel patterns & urine retention

Morphine (MS Contin) PO, IV, IM, SL, derm

MOA:

Classification:

Primary use:

Adverse Effects:

Nursing Considerations: (5)

MOA: binds to mu & kappa receptors to slow transmission of pain response

-Classification: opioid receptor agonist

-Primary use: to relieve moderate to severe pain; higher doses at end of life; ACS chest pain (usually drug of choice for hospice)

-Adverse Effects: respiratory depression, sedation, hypotension, itching

Nursing Considerations:

-Pts should never open capsules or crush extended release forms of opioids

-Careful assessment of vitals especially w/ opioid naive

-Potential for tolerance, monitor for abuse

-Avoid alcohol w/ use of morphine containing products

-close monitoring of bowel patterns & urine retention

hydromorphone (Dilaudid) PO, IV, IM

MOA:

Classification:

Primary Use:

Adverse Effects:

Nursing Considerations:

MOA: Binds to opioid receptors in the CNS, inhibiting ascending pain pathways -> altering the perception of & response to pain

Classification: opioid analgesic

Primary Use: to relieve moderate to severe pain; higher doses at end of life

Adverse Effects: respiratory depression, sedation, ortho hypotension, itching

Nursing Considerations:

-low equianalgesic dose as compared to Morphine (1mg PO hydromorphone = 8mg PO morphine) (more potent than morphine)

-On Beers Criteria (drugs not handled well by elderly pts)

-Potential for tolerance, monitor for abuse

-Avoid alcohol w/ use of morphine containing products

-close monitoring of bowel patterns & urine retention

fentanyl (Duragesic, Sublimaze, Fentora, Actiq) IV, IM, top, PO - lozenge (buccal)

MOA:

Classification:

Primary Use:

Adverse Effects: (4)

Nursing Considerations: (5)

MOA: binds w/ stereospecific receptors at many sites w/in the CNS, increases pain threshold, alters pain reception, inhibits ascending pain pathways

Classification: anilidopiperidine opioid

Primary Use: for use in moderate to severe pain - often used post operative

Adverse Effects: respiratory depression!, sedation, ortho hypotension, itching

Nursing Considerations:

-Dosed in mcg, not mg!!! (in small amounts, can be lethal)

-Assess for pts w/ > once patch. When applying transdermal patch, remove old one & correct dispose of patch

-Monitor VSs, level of consciousness, & respiratory rate

-Potential for tolerance, monitor for abuse

-Close monitoring of bowel patterns & urine retention

Hydrocodone with Acetaminophen (Lortab, Norco, Vicodin) PO

MOA:

Classification:

Primary Use:

Adverse Effects:

Nursing Considerations: (5)

MOA: binds to opiate receptors in the CNS, altering the perception of & response to pain; suppresses cough in medullary center

Classification: Opioid analgesic

Primary Use: for use in moderate to severe pain

Adverse Effects: respiratory depression, sedation, ortho hypotension, itching

Nursing Considerations:

-Initiate dosage lower in opioid naive & geriatric pts

-Administer w/ food or milk to decrease GI distress

-Monitor vital signs & level of conciousness

-Close monitoring of bowel patterns & urine retention

-Potential for tolerance, monitor for abuse

Codeine (Tylenol #3, Tylenol #4) PO

MOA:

Classification:

Primary Use:

Adverse Effects:

Nursing Considerations: (4)

MOA: binds to opioid receptors in the CNS, causing inhibition of ascending pain pathways; causes cough suppression by direct central axn in the medulla; produces generalized CNS depression

-Classification: opioid, antitussive

-Primary Use: Moderate pain (post op); cough; dental pain

-Adverse Effects: respiratory depression, sedation, itching

Nursing Considerations:

-On Beers criteria (avoid w/ geriatric pts)

-Potential for tolerance, monitor for abuse

-Monitor vital signs & level of conciousness

-Close monitoring of bowel patterns & urine retention

Burprenorphine (Buprenex, Butrans) SL, SQ, Top, IM, slow IV

MOA:

Classification:

Primary Use:

Adverse Effects:

Nursing Considerations: (2)

MOA: binding to mu opiate receptors in the CNS; displays partial mu agonist & weak kappa antagonist activity; analgesic effects plateau at higher doses & it then behaves like an antagonist

Classification: Mixed opioid agonist-antagonist (aka: opioid partial agonist)

Primary Use: opioid addiction; suppress symptoms of opioid withdrawal (not for pain usually)

Adverse Effects: respiratory depression, sedation, ortho hypotension

Nursing Considerations:

-Still has potential for respiratory depression, nausea, etc.

-Assess LFTs & VS

Naloxone (Narcan) IV, IM, intranasally

MOA:

Classification:

Primary Use:

Adverse Effects:

Nursing Considerations: (3)

MOA: interact w/ mu & kappa receptors

Classification: opioid receptor antagonists

Primary Use: to reverse respiratory depression & other acute symptoms of addiction, toxicity, overdose

Adverse Effects: minimal toxicity, increased BP, tremors, aggression (may be in severe withdrawal or pain after administering)

Nursing Considerations:

-Monitor respiratory rate (less than 12/min) or over sedation

-Keep resuscitative equipment accessible

-Not effective for respiratory depression caused by nonopioid medication (ONLY works for opioid overdose)

Paradigm Shift in Pain Management (4)

Change medical perspective & lingo when discussing pain

-Identification of multi modal analgesia methods

-Pt. education (risks of dependence, wut pain requires opioids)

-Improved engagement of all key players