Pain relief Flashcards

Question

Opioid skeleteal muscle effects periop

Answer 1

Skeletal muscle rigidity in chest(wooden chest), abdomen, jaw and extremities -Especially with large rapidly administered opioid doses -Common with fentanyl, sufentanil, and hydromorphone -Can make ventilation difficult or impossible (Wooden Chest) -High airway pressures from increase intrathorcic pressures/decrease venous return -Glottic rigidity and glottic closure have been reported

Answer 2

Dose dependent respiratory depression - Smaller doses: Usually increased Vt with decreased RR; overall decrease in minute ventilation (↑CO2, ↓O2) - Larger doses decreased Vt - Decrease compliance in chest wall - Constriction of pharyngeal and laryngeal muscles - Cough suppression - Decreased response to hypercarbia and hypoxia - Morphine and Meperidine = histamine related bronchoconstriction - Ventilatory depression #1 reason people die from OD

Answer 3

Shift to the right and slope is decreased - wont clear CO2 very well - be careful with pt with increased ICP

Answer 4

``` Depends on context: amount of pain/surgical stimulation, natural sleep -Intermittent bolus vs. cont. infusion (less spiking, less meds) -Speed of injection -Concurrent admin with other anesthetics -Decreased clearance -Age ```

Answer 5

-almost always IM or IV -For severe acute pain -PO for chronic pain and cancer pain --slow release--delayed onset 3-5hrs (not used in preop or intraop) *Considerable first pass effect -1/2 life 3-4hrs converted to active metabolite (morphine-6-glucuronide)

Answer 6

- Mild Pain Relief - PO - E1/2t = 3 hour - PO combined with APAP, guaifenesin, promethazine * *Prodrug: 10% is metabolized by CYP2D6 to its active form - Remaining drug is demethylated to inactive metabolite * *Active form = morphine - 10% Caucasians, 30% Asians lack 2D6 -- no analgesic effect - Antitussive (cough) effect remains even without conversion(enzyme)--Better for cough (lower dose) than pain relief

Answer 7

AKA – Vicodan (hydrocodone + APAP) - PO - Always combined with either APAP, ASA, ibuprofen, antihistamine - Analgesic and antitussive - Used for chronic pain - High abuse potential (dangerous bc of APAP)

Answer 8

PO -AKA Oxycontin, Percocet, Percodan -Available in sustained release preparation (oxycontin) -Moderate to severe pain; useful for chronic pain, post- op pain -Also in combination with APAP and ASA -No active metabolites - safer in patients with renal dysfunction -High abuse potential

Answer 9

PO, IV, SubQ - Synthetic - Long plasma half-life- 8-59 hours or 13-100 hrs - Opioid addiction treatment (maintenance) dosed QD - No active metabolites - safer in patients with renal dysfunction - Chronic pain syndrome treatment: doses BID or TID (q4-8 hr) - Tx: Neuropathic pain, chronic pain, opioid addiction tx - At risk for severe respiratory depression secondary to prolonged and unpredictable E1/2t

Answer 10

Competitive antagonist

Answer 11

Tolerance is common with chronic use of opioids (after 2-3 weeks of use) - Pt first notices a reduction in adverse effects - Shorter duration of analgesia - Followed by decrease in effectiveness of each dose - Tolerance to most adverse effects include: - Respiratory and CNS depression - Can be overcome by increasing the dose - -Switching opioid-tolerant patients to methadone may improve pain relief - Tolerance to sedative and emetic effects develop rapidly but not constipation - A stimulant laxative with or without a stool softener should be started early in tx - ex: senna/docusate

Answer 12

Cross-tolerance exists among all full agonists but is not complete (not 1:1) -When switching to another opioid, start with half or less of the equianalgesic dose

Answer 13

- Physical dependence causes abstinence symptoms upon sudden D/C - Clinically significant dependence develops only after several weeks of chronic tx - Addiction involves psychological dependence and biologic and social factors - Cancer pain and acute pain patients rarely experience euphoria and even more rarely develop psychological dependence or addiction

Answer 14

-Dose vary widely from one pt to another -No minimum or maximum dose except limitation by the dose of APAP or aspirin -“Weak” vs “strong” terminology usually inappropriate (codeine exception) - can dose different drugs so that they are equivalent -Dose required to maintain optimum pain relief with tolerable side effects must be used -After initial titration with short-acting opioid in the first 12 to 24 hrs, dose determination by around-the-clock dosing is recommended

Answer 15

- A sustained release formulation should be used in chronic pain - Immediate release doses that are 10 to 15% of the total daily dose should be used for breakthrough pain - PCA, given IV, SQ or other routes are now widely used when the oral route are not feasible

Answer 16

Analgesia a result of diffusion of the drug -Across the dura to mu receptors in substantia gelatinosa -Into the vasculature – systemic effect -Opioids given epidural or spinal have different onset, duration, and side effects as same drug given IV -Opioids placed in epidural space may undergo uptake into fat, systemic absorption or diffusion into CSF: get both spinal and systemic --Lipid soluble get resp depression sooner --Water soluble (morphine) stays in CSF then hits the brain stem get resp depression 24 hrs later

Answer 17

Cephalad movement of opioid in the CSF depends on lipid solubility -Highly lipid soluble will be limited in migration by uptake into the spinal cord ie. fentanyl **Whereas less soluble opioid will remain in CSF for transfer to cephalic location ie. Morphine -Penetration into CSF/vasculature depends upon lipid solubility -More lipid soluble, quicker peak CSF/systemic concentration

Answer 18

Dose for epidural is 5-10X higher than spinal dose | -May reduce local anesthesia dose in epidural/spinal as reducing overall anesthetic requirements

Answer 19

Acetaminophen Acetylated Salicylate NSAIDS Cyclooxygenase-2 Specific Inhibitors

Answer 20

- Ibuprofen (Motrin) - Naproxen (Naprosyn) - Oxaprozin (Daypro) - Diclofenac (Voltaren) - Etodolac (Lodine) - Indomethacin (Indocin) - Ketorolac (Toradol) - Nabumetone (Relafen) - Sulindac (Clinoril) - Tolmetin (Tolectin) - Piroxicam (Feldene) - Meloxicam (Mobic)

Answer 21

- First line agents for mild to moderate pain - Ceiling effect of ASA and APAP between 650 and 1300 mg - NSAIDs other than aspirin - analgesic ceiling may be higher - Exceeding the ceiling dose of any of these drugs will result in increased adverse effects with no added efficacy - Tolerance does not develop to the analgesic effects of these drugs

Answer 22

Central anti-prostaglandin effect - Antipyretic - Pain reduced via blockade of: NMDA receptor activation in CNS and Substance P in spinal cord - weak anti-inflammatory action (not a true NSAID) - Good choice in: - -Peptic ulcer disease - -Pediatric patients (safe) - Patients who need well functioning platelet

Answer 23

PO similar potency as ASA (in single analgesic doses, has same time-effect curve) - PO Dose = 325-650 mg Q4-6 hrs - IV formulation just FDA approved in US in 2010. - IV dose 1 gram over 15 minutes infusion only q4-6 hours not to exceed ***4000mg in 24 hours (check to make sure no other sources of acetaminophen)

Answer 24

- IV give at end of case because of plasma concentration | - Conjugated and hydroxylated to inactive metabolites; very little excreted unchanged by kidneys

Answer 25

Overdose can cause serious or fatal hepatic injury - Liver can only metabolize a limited amount of the hepato- toxic metabolite N-acetyl-p-benzoquinone with glutathione - When glutathione outnumbered by OD of acetaminophen hepatic injury occurs - Maximum safe dose 4 grams per day - Safe dose even lower in ETOH abuse (use caution) - Also increased risk of toxicity in patients taking **isoniazid - Acetylcysteine can substitute for glutathione and prevent hepatic injury if given within 8 hours of OD

Answer 26

- Renal papillary accumulation of metabolites can cause renal cell necrosis - May be responsible for development of some cases of ESRD - However, NSAIDS higher risk of renal toxicity than acetaminophen

Answer 27

* NSAIDS and ASA: - Arachadonic acid is released from phospholipids by the enzyme phospholipase A2 - Arachadonic acid is immediately metabolized by either: - -Cyclooxygenase - -Lipoxygenase - -Epoxygenase

Answer 28

- Prostaglandins - Prostacylcin - Thromboxanes

Answer 29

Leukotrienes | lipoxins

Answer 30

Epoxyeicosatetraenoic acid ( 4 types ) – regulates inflammation further research necessary to determine precise role

Answer 31

``` Cox1: prostaglandins: -Gastric Protection -Hemostasis -Renal Function COX2: prostaglandins -Pain -Fever -Inflam *block Cox 2 then increased the other half of the pathway. Thats why selective COX2 blockers were dangerous increased platelet aggregation and put puts at risk for Stroke and MI *NSAIDS block both sides ```

Answer 32

Aspirin effective in most mild to moderate pain - HA muscle pain, arthritis - Antipyretic - MI/stroke prevention; protection during MI (anti-plt) - IRReversible inhibition of COX, if going to hold before sure have to hold for a least a week - Single dose inhibits platelet function for lifetime of platelet (8-10 days) - Large doses can also decrease prothrombin

Answer 33

ESRD: NOT induced by chronic ASA - Prolonged bleeding (up to 15 minutes) in these patients with ASA - Can increase LFTs (usually reversible) - Single dose can potentiate asthma in aspirin-sensitive patients - Cross-sensitivity with other NSAIDS - can cause GI bleeding, PUD - CNS stimulation tinnitus

Answer 34

*Analgesic vs anti-inflammatory dosing -Analgesic/antipyretic: 325-650mg -Anti-inflammatory: 1000mg (3-5 g/day) -Increase dose gradually -Follow serum salicylate levels -Rarely used due to GI side effects *Hepatic clearance -E1/2t is 15-20 minutes for aspirin and 2-3 hrs for the active metabolite salicylic acid *Salicylate overdose: metabolic acidosis, tinnitis

Answer 35

Aspirin should not be used during viral syndromes in children and teenagers because of risk of Reye’s syndrome

Answer 36

- Helpful for arthritis related pain, musculoskelatal pain, headaches and dysmenorrhea → **ceiling effect with post-op pain! - More effective than full doses of aspirin or APAP - Equal or greater than usual doses of an opioid combined with APAP - Anti-Inflamm

Answer 37

- Similar efficacy at equipotent doses - Patient-to-patient differences - Toxicity differences

Answer 38

Cyclooxygenase (COX) inhibition - Blocks conversion of arachidonic acid to prostaglandins (PGs) - Decreases production and release of PGs - Reversible inhibition of platelet aggregation - -Inhibition of COX-1 blocks synthesis of thromboxane A2 which inhibits platelet aggreg - Analgesic, anti-inflammatory, antipyretic activity (cox2 side) - Weak acids - well-absorbed - Highly protein-bound >95% - Small Vd (non-specific NSAIDS) - Extensively metabolized and excreted in urine - Half-life varies from 12 hrs

Answer 39

Asthma and anaphylactic reaction in aspirin-sensitive patients - no physical dependence - Rare adverse effects: - Hepatic injury - Aseptic meningitis - Pregnancy - Best avoided but Category B if necessary - Avoid in 3rd trimester, Category D, due to premature closure of DA

Answer 40

- Renal injury - Gastric ulceration - Excessive bleeding - Impaired bone healing (consult with surgeon)

Answer 41

Dyspepsia, GI bleeding, PUD *Inhibition of PGs that maintain normal gastric and duodenal mucosa -Increases acid production -Decreases mucus production, gastric blood flow *Local irritation -Lipid soluble at low pH - enter gastric mucosal cells - lose lipid solubility - become trapped in cell *Risk factors -High doses, prolonged use, previous GI ulcer or bleeding, excessive ETOH intake, elderly, corticosteroid use

Answer 42

Low Risk -Ibuprofen and naproxen at low doses -Etodolac, sulindac -Celecoxib Moderate Risk -Ibuprofen and naproxen at mod-high doses -Diclofenac, oxaprozin, meloxicam, nabumetone High Risk -Tolmetin, piroxicam, aspirin, indomethacin, keto

Answer 43

Decreased synthesis of renal vasodilator PGs (PGE2): - Leads to decreased renal blood flow - Fluid and sodium retention - May cause renal failure or hypertension - Interstitial nephritis (rare) - In healthy people rarely of clinical significance - Risk factors (i.e. people who require prostaglandins for renal perfusion) - -Old age, CHF, HTN, DM, renal insufficiency, ascites, volume depletion, diuretic therapy

Answer 44

Can occur with all NSAIDs * Increased risk - Longer half-life - Highly potent COX inhibitors: Ketorolac, indomethacin - Higher dose * “Renal sparing” (lower risk, not devoid) - Sulindac, nabumetone - Celecoxib

Answer 45

Displaces other highly protein-bound agents -Increases levels of warfarin, phenytoin, sulfonylureas, sulfonamides, digoxin -Reduces effect of diuretics, β-blockers, ACEIs via suppression of renal PGs (angiotensin 2) -Increases lithium levels -Increased risk of GI bleed when combined with anti- coagulants -Probencid (gout drug) increases levels of most NSAIDs: Avoid with ketorolac

Answer 46

-IM or IV comparable to mild opioids -similar time to pain relief with ketorolac or morphine -Advantage: No ventilatory or cardiac depression -Adverse effects similar to typical NSAID: -Increased bleeding time and peri-op blood loss, Serious GI bleeding, ulceration, perforation and/or renal toxicity can occur (especially in the elderly or hypovolemic), potential for life-threatening bronchospasm

Answer 47

Do not exceed 5 days of use - IV onset ~ 10 minutes - E1/2t: 5 hours (prolonged in elderly 30-50%) - DOA: 6-8 hours - 99% protein bound - Conjugated in the liver - Dose IV: 30mg IV X 1 or q 6 hours - Daily max dose 120mg - Elderly: if you use at all cut dose in 1/2

Answer 48

- Celecoxib (Celebrex) only agent available - Withdrawn from the market due to increased MI risk: Rofecoxib (Vioxx), Valdecoxib (Bextra) - Selectively inhibit COX-2 - No more effective at reducing pain and inflammation - COX-1: gastric protection and production of TxA2 (vasoconstrictor, platelet aggregator) - COX-2: production of prostacyclin (vasodilator, platelet inhibitor) - Same risk of renal adverse effects

Answer 49

Use the lowest effective dose: < 200 mg/day, 200 mg/day = naproxen 500 mg BID - Consider patient’s risk for cardiovascular events - Consider patient’s risk for GI events - PO - Should still be taken with food - Avoid in patients with a sulfonamide allergy

Answer 50

``` ANTIdepressents: -TCAs (amitriptyline, nortriptyline, etc.) -Venlafaxine (Effexor) -Duloxetine (Cymbalta) ANTIconvulsants: Gabapentin (Neurontin) -Pregabalin (Lyrica) -Carbamazepine (Tegretol) -Phenytoin (Dilantin), Sodium Valproate (Depakote), Clonazepam (Klonopin), and Topiramate (Topamax) -Lamitrogen (Lamictal) ```

Answer 51

1st generation antihistamine | Low-dose IV/IM add analgesic effect to opioids in cancer and post operative pain while reducing incidence of N&V

Answer 52

Can produce analgesia in some patients with inflammatory diseases or tumor infiltration of nerves

Answer 53

5% Lidocaine (lidoderm) approved for post herpetic neuralgia -Topical EMLA useful for cutaneous anesthesia -Capsaicin cream (Zostrix) for neuropathic and osteoarthritic pain -Transdermal clonidine patch may improve pain and hyperalgesia in sympathetically maintained pa

Answer 54

- have a more favorable toxicity profile - -Do not interfere with platelet aggregation - -Rarely associated with GI bleeding - -Well tolerated by asthmatic patients

Pain relief Flashcards

(78 cards)