NALFON
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NALFON (NALFON).
Fenoprofen, a propionic acid derivative, nonselectively inhibits cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), reducing prostaglandin synthesis.
| Metabolism | Primarily hepatic via glucuronidation and hydroxylation; minor involvement of CYP2C9. |
| Excretion | Renal: 90% (mostly as glucuronide conjugates and unchanged drug; unchanged drug ~1-5%); Fecal: <5%; Biliary: negligible. |
| Half-life | 3-4 hours (terminal half-life in healthy adults; prolonged in elderly and hepatic impairment). |
| Protein binding | 99% (primarily to albumin). |
| Volume of Distribution | 0.15-0.2 L/kg (small, reflecting high protein binding and limited extravascular distribution). |
| Bioavailability | Oral: ~100% (well absorbed; slight first-pass effect). |
| Onset of Action | Oral: 30 minutes (analgesic effect). |
| Duration of Action | 4-6 hours (analgesic effect). |
| Molecular Weight | 255.27 |
NALFON (fenoprofen) 200-600 mg orally 3-4 times daily; maximum dose 3200 mg/day.
| Dosage form | TABLET |
| Renal impairment | Creatinine clearance 30-80 mL/min: reduce dose to 200 mg every 6-8 hours. Creatinine clearance <30 mL/min: avoid use. |
| Liver impairment | Child-Pugh class A or B: use with caution, reduce dose by 50%. Child-Pugh class C: contraindicated. |
| Pediatric use | Not recommended for pediatric use; safety and efficacy not established. |
| Geriatric use | Start at lowest effective dose (200 mg 3-4 times daily); monitor renal function and gastrointestinal bleeding risk. |
| 1st trimester | Avoid; associated with oligohydramnios and fetal renal impairment; risk of miscarriage and cardiac malformations. |
| 2nd trimester | Avoid; may cause oligohydramnios and premature closure of ductus arteriosus. |
| 3rd trimester | Contraindicated due to risk of premature closure of ductus arteriosus and oligohydramnios. |
Clinical note
Comprehensive clinical and safety monograph for NALFON (NALFON).
| Placental transfer | Crosses placenta; limited human data, but NSAIDs are known to cross readily. |
| Breastfeeding | Excreted into breast milk in low amounts; use with caution due to potential adverse effects in infant (e.g., renal impairment, gastrointestinal bleeding). |
| Lactation Rating |
■ FDA Black Box Warning
Nonsteroidal anti-inflammatory drugs (NSAIDs) cause an increased risk of serious cardiovascular thrombotic events, including myocardial infarction and stroke, which can be fatal. This risk may occur early in treatment and may increase with duration of use. NALFON is contraindicated in the setting of coronary artery bypass graft (CABG) surgery.
| Serious Effects |
Hypersensitivity to fenoprofen or any NSAIDHistory of asthma, urticaria, or allergic-type reactions after aspirin or NSAIDActive peptic ulcer disease or history of recurrent ulcerationSevere renal impairment (CrCl <30 mL/min)Advanced renal diseaseCardiovascular disease risk (use caution)
| Precautions | Cardiovascular thrombotic events, Gastrointestinal bleeding, ulceration, and perforation, Renal toxicity including renal papillary necrosis, Hepatic toxicity, Hypertension, Anaphylactoid reactions, Exacerbation of asthma |
| Food/Dietary | Avoid alcohol as it increases risk of GI bleeding. May be taken with food or milk to reduce GI irritation. No specific food restrictions beyond general healthy diet. |
Loading safety data…
| L3 (Moderately Safe) |
| Teratogenic Risk | NSAIDs including NALFON are associated with increased risk of fetal renal dysfunction, oligohydramnios, and premature closure of the ductus arteriosus, particularly in the third trimester. First trimester exposure may be associated with a small increased risk of cardiac defects and gastroschisis, but data are limited. Avoid use after 30 weeks gestation due to risk of premature ductus arteriosus closure. |
| Fetal Monitoring | Monitor maternal renal function, blood pressure, and signs of bleeding. In pregnancy, fetal monitoring with ultrasound for oligohydramnios and ductus arteriosus Doppler if used beyond 20 weeks. Assess for premature ductus arteriosus closure in third trimester. |
| Fertility Effects | Nonsteroidal anti-inflammatory drugs (NSAIDs) like NALFON may impair female fertility by inhibiting ovulation through prostaglandin synthesis inhibition; this effect is reversible upon discontinuation. No known effect on male fertility at therapeutic doses. |
| Clinical Pearls | Nalfon (fenoprofen) is a NSAID with analgesic and anti-inflammatory properties; use lowest effective dose for shortest duration to minimize GI and renal risks; avoid in patients with severe renal impairment (CrCl <30 mL/min) or history of peptic ulcer; monitor renal function and BP periodically; may interfere with aspirin's antiplatelet effect; contraindicated in setting of CABG surgery. |
| Patient Advice | Take with food or milk to reduce stomach upset. · Avoid alcohol while taking this medication. · Report signs of GI bleeding (black/tarry stools, coffee-ground emesis) or cardiovascular events (chest pain, shortness of breath). · Do not exceed recommended dose or duration. · Inform healthcare provider of all other medications, especially blood thinners or other NSAIDs. · May cause dizziness or drowsiness; avoid driving until you know how this medication affects you. |