Dosing and uses of Nalfon (fenoprofen)
Adult dosage forms and strengths
capsule
- 200mg
- 400mg
tablets
- 600mg
Pain
200 mg PO q4-6hr; not to exceed 3200 mg/day
Rheumatoid Arthritis
300-600 mg PO q6-8hr
Maximum recommended dose is 3200 mg/day
Osteoarthritis
300-600 mg PO q6-8hr
Maximum recommended dose is 3200 mg/day
Renal Impairment
Advanced renal disease: Not recommended
Administration
Take with food or 8-12 oz water to avoid GI effects
Other Indications
Off-label: vascular headache, gout
Pediatric dosage forms and strengths
<12 years: Safety and efficacy not established
Geriatric dosage forms and strengths
Pain
200 mg PO q4-6hr; not to exceed 3200 mg/day
Rheumatoid Arthritis, Osteoarthritis
300-600 mg PO q6-8hr
Maximum recommended dose is 3200 mg/day
Nalfon (fenoprofen) adverse (side) effects
>10%
Dyspepsia (10.3%)
Somnolence
Increased LFt
1-10%
Abdominal pain
Anemia
Diarrhea
Dizziness
Edema
Headache
Constipation
Confusion
Tremor
Sweating
Tinnitus
Blurred vision
Palpitations
Nervousness
Fatigue
Rash
Nausea
Vomiting
GI bleeding, ulceration, perforation
Frequency not defined
Insomnia
Asthenia
Paresthesia
Muscle weakness
Decreased hearing
Purpura, bruising, hemorrhage
Thrombocytopenia, hemolytic anemia, aplastic anemia, agranulocytosis, pancytopenia, slight decreases in hemoglobin concentration & hematocrit
Dysuria, cystitis, hematuria
Nephrotic syndrome, renal failure, oliguria, anuria, azotemia, allergic nephritis, nephrosis, papillary necrosis
Jaundice
Cholestatic hepatitis
Warnings
Black box warnings
Cardiovascular Risk
- NSAIDs may increase risk of serious cardiovascular thrombotic events, myocardial infarction (MI), & stroke, which can be fatal
- Risk may increase with duration of use
- Patients with risk factors for or existing cardiovascular disease may be at greater risk
- NSAIDs are contraindicated for perioperative pain in the setting of coronary artery bypass graft (CABG) surgery (increased risk of MI & stroke)
Gastrointestinal Risk
- NSAIDs increase risk of serious GI adverse events including bleeding, ulceration, & perforation of the stomach or intestines, which can be fatal
- GI adverse events may occur at any time during use & without warning symptoms
- Elderly patients are at greater risk for serious GI events
Contraindications
Absolute: ASA allergy
Relative: bleeding disorders, duodenal/gastric/peptic ulcer, renal impairment, stomatitis, SLE, ulcerative colitis, upper GI disease, late pregnancy (may cause premature closure of ductus arteriosus)
Cautions
Use caution in asthma (bronchial), cardiac disease, CHF, hepatic impairment, HTn
Long-term administration of NSAIDs may result in renal papillary necrosis and other renal injury; patients at greatest risk include the elderly, or those with impaired renal function, hypovolemia, heart failure, liver dysfunction, salt depletion, and individuals taking diuretics, ACE inhibitors, or ARBs
Heart Failure (HF) risk
- NSAIDS have the potential to trigger HF by prostaglandin inhibition that leads to sodium and water retention, increased systemic vascular resistance, and blunted response to diuretics
- NSAIDS should be avoided or withdrawn whenever possible
- AHA/ACC Heart Failure Guidelines; Circulation. 2016; 134
Pregnancy and lactation
Pregnancy category: C; avoid during third trimester, may cause premature closure of the ductus arteriosus
The Quebec Pregnancy Registry identified 4705 women who had spontaneous abortions by 20 weeks' gestation; each case was matched to 10 control subjects (n=47,050) who had not had spontaneous abortions; exposure to nonaspirin NSAIDs during pregnancy was documented in approximately 7.5% of cases of spontaneous abortions and in approximately 2.6% of controls. (CMAJ, September 6, 2011; DOI:10.1503/cmaj.110454)
Lactation: excretion in milk unknown/not recommended
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Nalfon (fenoprofen)
Mechanism of action
Inhibits synthesis of prostaglandins in body tissues by inhibiting at least 2 cyclooxygenase isoenzymes, cyclooxygenase-1 (COX-1) and -2 (COX-2)
May inhibit chemotaxis, may alter lymphocyte activity, decrease proinflammatory cytokine activity, and may inhibit neutrophil aggregation. These effects may contribute to its anti-inflammatory activity
Pharmacokinetics
Onset: 2-4hr
Duration: 4-6 hr
Peak Plasma Time: 2 hr
Peak Plasma Concentration: 50 mcg/mL
Protein Bound: 99% (albumin)
Metabolism: Liver
Metabolites: 4'-hydroxyfenoprofen, glucuronic acid conjugates
Enzymes inhibited: cyclooxygenase-1 (COX-1) & -2 (COX-2), prostaglandin synthesis
Half-life: 2.5-3 hr
Clearance: within 24 hr
Excretion: urine (primarily); feces
