Pain Management Flashcards
Acetaminophen: (Tylenol) mechanism of action
- Mechanism of action: not fully known
- Acetaminophen acts within the central nervous system (CNS) to inhibit synthesis of prostaglandins.
- It may also work peripherally to block pain impulse generation.
- Does not have significant anti-inflammatory properties
- Inhibits synthesis of prostaglandins in the CNS to peripherally block pain impulse generation; produces antipyretic effect by inhibiting hypothalamic heat-regulating center. Does not have anti-inflammatory properties.
Ibuprofen: (Advil, Motrin) mechanism of action
• Decreases pain, temperature, and inflammation through inhibition of cyclooxygenase, thereby preventing prostaglandin synthesis
Nonselective/Selective NSAIDS mechanism of action
- All NSAIDs reduce fever and pain. Pain due to inflammation is better treated with NSAIDS than acetaminophen.
- The NSAIDs inhibit cyclooxygenase enzymes (COX-1 and COX-2), thus inhibiting prostaglandin synthesis.
Nonselective NSAIDs inhibit . . ?
both COX-1 and COX-2:
• The COX-2 specific agent celecoxib (Celebrex®) primarily inhibits COX-2; and at its therapeutic concentrations, the COX 1 enzyme is not inhibited
Selective NSAIDS include ?
- oxicams – meloxicam (Mobic®)
* coxibs – celecoxib (Celebrex®)
identify the recommended dosing range for acetaminophen (adults and children)
Adults: 325-650 mg every 4-6 hours (2 grams daily in those with underlying liver disease or who use alcohol chronically)
Pediatrics: 10-15mg/kg q 4-6 (MAX 5 doses in 24 hours)
Identify the recommended dosing range for ibuprofen for children
Ibuprofen (Advil, Motrin)
Pediatrics: 4-10 mg/kg q 6-8 (MAX 40 mg/kg/day)
• Do not use in infants <6 months of age
Identify the recommended dosing range for naproxen
Naproxen (generic, Naprosyn®):
250-500 mg twice daily (1500 mg daily maximum)
Identify the recommended dosing range for celecoxib
Celecoxib (CeleBREX®):
100 mg twice daily or 200 mg once daily (200 mg daily maximum)
State the maximum daily recommended dose for acetaminophen.
Must not exceed 4 grams daily to avoid the potential for adverse effects on liver function
• For patients with underlying liver disease or who use alcohol chronically, the total daily dose should not exceed 2 grams daily (and preferably be less than 2 grams daily) and the duration of use should be limited also.
Adverse effects of Acetaminophen (Tylenol)
relatively safe
• Long-term use may result in hepatotoxicity or renal toxicity.
• Risk for hepatotoxicity is greater in patients with liver disease or those who abuse alcohol (≥ 3 drinks daily)
• Risk for renal failure is more common in patients using a combination of acetaminophen and NSAIDs chronically.
Adverse effects of Nonselective NSAIDs
inhibit both COX-1 and COX-2
• COX-1 blockade with nonspecific NSAIDs can lead to GI ulcers and increased bleeding risk by inhibiting platelet aggregation.
• The COX-2 specific agent celecoxib (Celebrex®) primarily inhibits COX-2; and at its therapeutic concentrations, the COX 1 enzyme is not inhibited, thus GI toxicity may be decreased.
• COX 2 specific NSAIDs may increase platelet aggregation resulting in clotting events causing cardiovascular risk.
identify the patient factors that put them at risk for GI adverse effects of NSAIDs
- Minor complaints of nausea, dyspepsia, anorexia, and diarrhea, affect 10-60% of patients. Taking NSAIDs with food and milk is helpful to minimize this adverse effect
- GI bleeding and gastric mucosal injury resulting in gastric or duodenal ulcers may occur in 7-13%.
- Clinicians must determine a patient’s risk for GI toxicity (ulcer or bleeding) from an NSAID before starting one. Factors increasing risk include: history of complicated ulcer, use of multiple NSAIDs over time, including aspirin, use of an anticoagulant, age older than 70 years, and concomitant use of corticosteroids
- Black box warning: NSAIDs cause an increased risk of serious GI adverse reactions, including bleeding, inflammation, ulceration, and perforation of the stomach or intestines, which can be fatal. These events can occur at any time during use and without warning symptoms. Elderly patients are at greater risk of serious GI events
identify the patient factors that put them at risk for cardiovascular adverse effects of NSAIDs
- COX-2 specific NSAIDs have been associated with increased risk of cardiovascular events (e.g., myocardial infarction and sudden death) because of an increased potential for platelet aggregation in these patients.
- Black box warning: Nonsteroidal anti-inflammatory drugs (NSAIDs) may cause an increased risk of serious cardiovascular thrombotic events, myocardial infarction (MI), and stroke, which can be fatal. This risk may increase with duration of use. Patients with cardiovascular disease or risk factors of cardiovascular disease may be at greater risk.
identify the patient factors that put them at risk for renal adverse effects of NSAIDs
- NSAIDs can damage the kidney.
- NSAID-induced renal syndromes includes hyperkalemia, elevated blood pressure, peripheral edema, and weight gain.
- Mechanisms of injury include direct toxicity and inhibition of local prostaglandins
- Patients at high risk for kidney damage are those with kidney disease, heart failure, severe liver disease, older patients and medications that also damage the kidney
