1. NSAIDs, Acetaminophen Flashcards
2016 RxPrep p657
MOA of acetaminophen
Analgesic: thought to inhibit prostaglandin synthesis in the CNS and reduce pain impulse generation; may include the endogenous cannabinoid system and inhibit NMDA receptors
Antipyretic: mediated by inhibition of heat regulating centers in the brain
Lacks anti-inflammatory effects; does not inhibit thromboxane = no anti-platelet effects
acetaminophen (brand)
available as tablet/caplet, chewable tablet, ODT, injection, suspension, infant drops, suppository
Tylenol
Most “non-Aspirin” pain relievers
Ofirmev (IV)
FeverAll (rectal suppository)
acetaminophen dosing (for max/day, 325 mg, 500 mg, 650 mg, rectal suppository, and IV)
–Max: 4 g/day, 325 mg per Rx dosing unit in combo products
–325 mg: max 2 tab Q4-6h, NTE 10 tabs/day (3250 mg)
–500 mg: max 2 tab Q6h, NTE 6 tabs/day (3000 mg)
–650 mg ER: max 2 tab Q8h, NTE 6 tab/day (3900 mg)
–rectal supp: 650 mg Q4-6h, NTE 6 supp/day (3900)
–IV (for ≥50 kg): 650 mg Q4h (3900 mg) or 1g Q6h (4000 mg)
acetaminophen dosing (pediatrics)
–10-15 mg/kg Q4-6h; max 5 doses/day
–infant drops come in 160 mg/5 mL (like children’s suspension to avoid dosing confusion and toxicity risk)
–rectal supp: 80, 120, 325, 650 mg
acetaminophen BBW
May cause severe hepatotoxicity (potentially requiring liver transplant or resulting in death), usually associated with excessive acetaminophen intake (>4 g/day) or use of more than one acetaminophen containing product; risk of 10-fold dosing errors with injection
acetaminophen SEs
–Hepatotoxicity (possibly fatal)
–Severe skin rash (rare: SJS, TEN, AGEP - stop drug, seek immediate medical help)
–Nephrotoxicity (rare: usually with chronic overdose; generally safer than NSAIDs in renal disease)
acetaminophen is pregnancy category ___ (IV formulation)
C
often used for mild pain in pregnancy
avoid using ______ for acetaminophen on patient labels
APAP
acetaminophen safety consideration: use the _______ ____ or ______ provided with the medicine.
dosing syringe
cup
acetaminophen safety consideration: caution with IV acetaminophen. Concentration is 10 mg/mL (in 100 mL vials). Order in ___, not ____. Nurses should not be permitted to prepare doses; it should be prepared in the _____.
mg
mL
pharmacy
acetaminophen overdose:
–antidote: _________ (PO-Mucomyst, IV-Acetadote)
–MOA: restores [intra/extra]cellular ______
–administer immediately; even before the results of APAP level are obtained; within ___ hrs of ingestion
–Give ___ mg/kg PO loading dose, then ___ mg/kg PO Q4h x ___ doses (unless initial APAP level is non-toxic)
–Often causes N/V due to _____ of ______ ______
–N-acetylcysteine (NAC) (IV is more costly) –intra; glutathione –8 –140; 70; 17 –odor; rotten eggs
acetaminophen DDI: [may/may not] be used with warfarin; chronic use of >__ g/day can increase INR
may
2
acetaminophen DDI: avoid or limit _____ use due to risk of hepatotoxicity
alcohol (1 drink/day for women; 2 drinks/day for men)
acetaminophen counseling point: should see Dr. if self-treating condition worsens, persists for more than ___ days, experiencing a high fever >____ºF, rash, N/V, or blood in stool; this applies for ______ as well; _____ should be seen by a pediatrician.
2
102.5
children
infants
MOA of NSAIDs
–non-selective: block synthesis of COX-1 (binds reversibly) and COX-2
–selective: block COX-2 only (decreasing GI risk)
–salicylates (aspirin): inhibits COX-1 irreversibly
COX-1 vs COX-2
–both enzymes catalyze the conversion of arachidonic acid
–COX-1: cytoprotective prostaglandins to protect GI mucosa; thromboxane to aid platelet aggregation
–COX-2: inflammatory prostaglandins sensitize skin pain receptors, recruit inflammatory molecules, regulate hypothalamic temperature control
NSAID BBW
a MedGuide is required to address GI and CV risks
all NSAIDs, including aspirin BBW: GI risk (define)
Can occur at any time during use and without warning. _____ patients, those with a hx of GI bleed, pts taking ______ and those taking ____/____ are at greatest risk for serious GI events
GI risk: bleeding, ulceration, perforation of stomach and intestines, which can be fatal
Elderly
corticosteroids
SSRIs/SNRIs
all non-aspirin NSAIDs BBW: CV risk (define)
Can occur in first few ____ of use. Risk may be increased with ____ doses or _____ duration of use and in patients with ___ disease or ____ _____ for it.
CV risk: thrombotic events, MI, stroke, HF weeks higher longer CV risk factors
non-aspirin NSAID CI
treatment of perioperative pain in the setting of CABG surgery
aspirin/acetylsalicylic acid (brand, dosing)
available as tablet/caplet, chewable tablet, suppository
Ascriptin, Bufferin, Ecotrin:
cardioprotection dosing 81-162 mg; analgesic dosing 325-650 mg Q4-6h
Durlaza (Rx): 162.5 mg daily
GI bleed s/sx
–dark, tarry stools
–stomach upset
–weakness
–coffee-ground emesis (indicates a more serious, fast GI bleed)
non-acetylated salicylates (5)
–salsalate –magnesium salicylate –choline magnesium trisalicylate –diflunisal –salicylate salts
salsalate (brand, dosing)
generic only
up to 3 g/day divided BID-TID
