NAPRELAN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NAPRELAN (NAPRELAN).
Nonsteroidal anti-inflammatory drug (NSAID) that inhibits cyclooxygenase (COX-1 and COX-2), reducing prostaglandin synthesis, which mediates pain, inflammation, and fever.
| Metabolism | Primarily hepatic via CYP1A2 and CYP2C9; minor metabolism via glucuronidation and other pathways. |
| Excretion | Renal: 50-60% as metabolites and conjugates; biliary/fecal: ~5%; remainder uncharacterized. |
| Half-life | Terminal elimination half-life: 10-20 hours; context: allows twice-daily or once-daily dosing for chronic pain or inflammation. |
| Protein binding | >99% bound, primarily to albumin. |
| Volume of Distribution | 0.16 L/kg; clinical meaning: low Vd indicates limited tissue distribution, predominantly in plasma. |
| Bioavailability | Oral (conventional): ~95%; NAPRELAN: approximately 85% of conventional naproxen (due to controlled-release matrix). |
| Onset of Action | Oral: 1-2 hours (as conventional tablet); NAPRELAN (controlled-release): 2-4 hours. |
| Duration of Action | 12-24 hours; clinical note: NAPRELAN formulation provides sustained plasma levels for twice-daily dosing. |
| Molecular Weight | 373.45 |
750 mg to 1000 mg orally once daily, with or without food.
| Dosage form | TABLET, EXTENDED RELEASE |
| Renal impairment | CrCl <30 mL/min: avoid use; CrCl 30-59 mL/min: reduce dose to 500 mg once daily or use alternative. |
| Liver impairment | Child-Pugh Class B or C: reduce dose to 500 mg once daily or avoid use; monitor for toxicity. |
| Pediatric use | Not established for children under 18 years; safety and efficacy not determined. |
| Geriatric use | Initiate at lowest effective dose (e.g., 500 mg once daily); monitor renal function and adjust as needed. |
| 1st trimester | Avoid; NSAIDs are associated with increased risk of miscarriage and congenital malformations, particularly cardiovascular defects. |
| 2nd trimester | Use only if clearly needed; may cause oligohydramnios and fetal renal dysfunction with prolonged use. |
| 3rd trimester | Avoid; risk of premature closure of ductus arteriosus, oligohydramnios, and neonatal complications (e.g., pulmonary hypertension, renal impairment). |
Clinical note
Comprehensive clinical and safety monograph for NAPRELAN (NAPRELAN).
| Placental transfer | Crosses placenta; documented transfer in animal studies and human data. |
| Breastfeeding | Excreted into breast milk in low concentrations; due to potential adverse effects on infant renal function and cardiovascular system, use with caution or avoid, especially with prolonged therapy. |
■ 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. Naproxen is contraindicated in the setting of coronary artery bypass graft (CABG) surgery.
| Serious Effects |
Hypersensitivity to naproxen or any component of the formulationHistory of asthma, urticaria, or allergic-type reactions after taking aspirin or other NSAIDsActive peptic ulcer disease or gastrointestinal bleedingSevere hepatic impairment (Child-Pugh Class C)Severe renal impairment (CrCl <30 mL/min)Perioperative pain in the setting of coronary artery bypass graft (CABG) surgery
| Precautions | Cardiovascular risk (increased risk of MI and stroke); gastrointestinal risk (bleeding, ulceration, perforation); renal toxicity; hepatic impairment; asthma exacerbation; fluid retention; hypertension; anaphylactoid reactions; pregnancy (avoid in third trimester). |
| Food/Dietary | Take with food or milk to minimize GI irritation. Avoid alcohol. No specific food-drug interactions beyond general NSAID precautions. |
Loading safety data…
| Lactation Rating |
| L3 (Moderately Safe) - consider risk vs benefit. |
| Teratogenic Risk | Naproxen (NAPRELAN) is contraindicated in the third trimester due to risk of premature closure of ductus arteriosus and oligohydramnios. In first and second trimesters, use only if clearly needed; limited data suggest possible association with spontaneous abortion and cardiac defects, but absolute risk is low. |
| Fetal Monitoring | Monitor maternal renal function, blood pressure, and signs of bleeding. In third trimester, monitor amniotic fluid volume and fetal ductus arteriosus via ultrasound if prolonged use. Assess for fetal growth restriction with repeat ultrasound if used chronically. |
| Fertility Effects | NSAIDs including naproxen may impair female fertility by inhibiting prostaglandin synthesis, potentially delaying or preventing ovulation. Reversible upon discontinuation. Effects on male fertility are minimal. |
| Clinical Pearls | Naprelan (naproxen sodium) is a controlled-release formulation allowing once-daily dosing. Onset of action may be delayed; not suitable for acute pain requiring rapid relief. Use lowest effective dose for shortest duration due to cardiovascular and GI risks. Contraindicated in patients with aspirin allergy, perioperative pain in CABG surgery, and severe renal impairment. |
| Patient Advice | Take with food or milk to reduce stomach upset. · Swallow tablet whole; do not crush, chew, or split. · Avoid alcohol, as it increases risk of GI bleeding. · Report signs of GI bleeding, stroke, or heart attack immediately. · Do not use with other NSAIDs or aspirin without doctor approval. |