Pain Relief Flashcards
Nonselective COX inhibitors
Aspirin / Diclofenac / Ibuprofen / Indomethacin / Ketorolac / Naproxen / Piroxicam
COX-2 Selective Inhibitors
Celecoxib / Meloxicam
Risks of GI SEs (lowest risk)
Celecoxib, then Ibuprofen / Aspirin / Diclofenac
Risk of GI SEs (high risk)
Piroxicam is highest, Naproxen / Indomethacin is medium risk
Celecoxib
Only selective COX-2 inhibitor available in US
SE: sulfonamide so may cause HS reactions (rashes)
Meloxicam
Preferential COX-2 inhibitor but not as selective as celecoxib
NSAIDs Uses
Tx of mild to moderate pain (especially related to inflammation), RA, OA, gout, ankylosing spondylitis, dysmenorrhea
Aspirin Uses
Tx flushing induced by release of PGD2 when pt is taking Niacin for lowering serum cholesterol
NSAIDs SEs
GI, CVS, renal and aspirin HS
NSAID renal SEs
Decrease in renal blood flow d/t decreased PG activity on the afferent arteriole, and Analgesic Nephropathy
NSAID interaction w/ ACEIs
NSAIDS may diminish the antihypertensive effect of ACE-inhibitors by blocking the production of vasodilating PGs
Triple Whammy drug interactions
Risk of acute kidney injury when ACEI (or ARB) is combined w/ a diuretic and NSAID
- NSAIDs: constrict afferent and reduce GFR
- ACEIs/ARBs: dilate efferent and decrease GFR
- Diuretics: reduce plasma volume and GFR
NSAIDs interactions with Warfarin
NSAIDS may increase risk of bleeding in pt’s receiving Warfarin
NSAIDs Contraindications
Associated with Reye’s Syndrome, so CI in children and young adults < 20yo w/ fever associated viral illness; CI in pregnancy
Aspirin (general)
MOA: irreversibly inhibits COX
Metabolism: deacetylated by esterases in body producing salicylate
Effects: uncouple ox-phos leading to elevated CO2 and hyperventilation
Aspirin SE
Epigastric distress, prolonged BT, Reye’s Syndrome, HS, uricosuric effects (at low doses competes w/ uric acid for secretion and thus reduces uric acid secretion), hepatic injury,
Salicylate Intoxication
Sx’s: HA, dizziness, tinnitus, confusion, hyperventilation
Complication: mixed respiratory alkalosis and metabolic acidosis; cause of death usually respiratory failure
Acetaminophen
MOA: analgesic and antipyretic (not technically NSAID)
Use: mild to moderate pain, DOC for pain relief in OA, DOC for children with fever/flu, DOC for pain in pregnancy, adjunct to antiinflammatory therapy
SE: hepatotoxic (antidote - Acetylcysteine)
Opioids inhibiting Serotonin reuptake
Methadone / Meperidine / Tramadol / Fentanyl
*results in Serotonin Syndrome
Opioids CI
Not recommended to use concurrently with MAOIs d/t risk of developing Serotonin Syndrome
Oxymorphone
MOA: high affinity for μ receptors, low affinity for δ and κ receptors
Use: DOC for severe pain
Heroin
MOA: heroin is rapidly hydrolyzed to 6-MAM then hydrolyzed to morphine
Effects: heroin and 6-MAM are more liposoluble than morphine
Meperidine
μ receptor agonist
PK: t1/2 of 3h
Use: short term tx of acute pain
Fentanyl
μ receptor agonist
MOA: rapid onset w/ short duration of action, 100x more potent than morphine
Use: severe acute pain
Methadone
MOA: μ receptor agonist, NMDA receptor antagonist, 5-HT and NE reuptake inhibitor
PK: long t1/2 and less profound sedation and euphoria
Effect: abstinence syndrome is prolonged but less severe
Use: detoxification for heroin addict
SE: QT prolongation, torsades
Levorphanol
μ, δ, and κ agonist
MOA: serotonin and NE reuptake inhibitor, NMDA receptor antagonist
Use: severe pain
Oxycodone
Use: moderate to severe pain
Hydrocodone
Use: moderate to severe pain
*combo w/ acetaminophen or NSAID
Codeine
Use: mild to moderate pain
Metabolism: converted to morphine by CYP2D6
Pentazocine / Butorphanol / Nalbuphine
κ agonist and μ antagonist
Use: potent analgesics in opioid-naive patients but precipitate withdrawal in pt’s that are dependent on opioids
SE: psychotomimetic effects, not recommended as routine analgesics bc they have ceiling effect
*2nd and 3rd line drugs
Buprenorphine
κ antagonist and μ agonist
Use: tx opioid addiction (there is ceiling effect)
*2nd line drug
Tramadol
Weak μ agonist and NE and serotonin reuptake inhibitor
Use: moderate pain, neuropathic pain, osteoarthritis
SE: increased risk of sz in pt w/ sz disorder
Naloxone
μ, δ, and κ antagonist
Use: tx of acute opioid overdose (if respiratory center is compromised)
Naltrexone
μ, δ, and κ antagonist
Use: opioid and ETOH addiction
Dextromethorphan and Codeine
Antitussives
MOA: different receptors, effect is achieved at lower doses than for analgesia
Diphenoxylate and Loperamide
MOA: μ receptors on enteric nerves, epithelial cells and muscle
Effect: decrease motility of smooth muscle
Use: tx diarrhea
TCAs (names)
Secondary amines: Desiparimine / Notriptyline *(preferred in elderly pt’s)
Tertiary amines: Amitryptyline / Imipramine
Venlafaxine / Duloxetine
Selective serotonin and NE reuptake inhibitor (SNRI)
Use: tx of chronic musculoskeletal/neuropathic pain (osteoarthritis)
SE: nausea, sexual dysfunction, somnolence
Gabapentin / Pregabalin
MOA: block voltage gated Ca2+ channels
Effect: decrease release of Glu, NE, and substance P
SE: dizziness, somnolence, peripheral edema
Carbamazepine
Anticonvulsant
MOA: block voltage gated Na+ channels
Use: DOC for trigeminal neuralgia
SE: drowsiness, dizziness, N/V, leukopenia, aplastic anemia
Dexamethasone
Use: DOC for acute nerve compression, increased IOP, bone pain ,anorexia, nausea, depressed mood
Hydroxyzine
May add to analgesic effects of opioids, can manage pruritis and N/V SEs caused by opioids
Clonidine
Available as oral and transdermal patches, may improve pain and hyperalgesia in sympathetically maintained pain
Lidocaine
Patch approved for postherpetic neuralgia
Capsaicin
Patch approved for postherpetic neuralgia
Use: osteoarthritis (topical application)
SE: severe skin burns and nerve damage at site of application; coughing/sneezing/eye irritation when the residue dries
Caffeine
May enhance analgesic effect of acetaminophen and NSAIDs
TCA Precautions/CIs
Caution: angle-closure glaucoma, BPH, urinary retention, constipation, CVD, liver dz
CI: 2nd or 3rd degree ❤️ block, arrhythmias, prolonged QT, severe liver dz, recent acute MI
TCAs SE
Constipation, dry mouth, blurred vision, AMS, tachycardia, urinary hesitation…sexual dysfunction, orthostatic hypotension, wt gain, sedation
