naproxen
EC-Naprosyn, Naprosyn

naproxen sodium
Aleve, Anaprox, Anaprox DS, Naprelan

Available forms
Available by prescription only
naproxen
Oral suspension: 125 mg/5 ml
Tablets: 250 mg, 375 mg, 500 mg
Tablets (delayed-release): 375 mg, 500 mg
naproxen sodium
Tablets (controlled-release): 412.5 mg, 550 mg
Tablets (film-coated): 275 mg, 550 mg Available without a prescription
naproxen sodium
Caplets, gelcaps, tablets: 220 mg

Indications and dosages
 Mild to moderately severe musculoskeletal or soft tissue irritation.
naproxen. Adults: 250 to 500 mg P.O. b.i.d. Or, 250 mg in the morning and 500 mg in the evening. Or, 375 to 500 mg P.O. b.i.d. delayed release.
naproxen sodium. Adults: 275 to 550 mg P.O. b.i.d. Or, 275 mg in the morning and 550 mg in the evening. Or, 750 to 1,000 mg P.O. once daily (controlled-release). Maximum daily dose is 1,500 mg for limited periods.
 Mild to moderate pain, primary dysmenorrhea.
naproxen. Adults: 500 mg P.O. to start, followed by 250 mg P.O. q 6 to 8 hours or 500 mg P.O. q 12 hours, p.r.n. Maximum, 1,250 mg naproxen daily.
naproxen sodium. Adults: 550 mg P.O. to start, followed by 550 mg P.O. q 12 hours or 275 mg P.O. q 6 to 8 hours, p.r.n. Maximum, 1.375 g naproxen sodium daily. For self-medication, 220 mg q 8 to 12 hours. Maximum, 660 mg for adults younger than age 65 or 440 mg daily for adults age 65 and older. Tell patient not to self-medicate for longer than 10 days.
 Acute gout.
naproxen. Adults: 750 mg P.O. initially; then 250 mg q 8 hours until episode subsides.
naproxen sodium. Adults: 825 mg P.O. initially; then 275 mg q 8 hours until attack has subsided. Or, 1,000 mg to 1,500 mg (controlled-release tablets) P.O. daily on the first day; then 1,000 mg P.O. daily until attack subsides.
 Juvenile rheumatoid arthritis. naproxen. Children: 10 mg/kg daily P.O. in two divided doses.

Pharmacodynamics
Analgesic, antipyretic, and anti-inflammatory actions: Mechanisms of action are unknown; naproxen is thought to inhibit prostaglandin synthesis.

Pharmacokinetics
Absorption: Absorbed rapidly and completely from the GI tract. Naproxen sodium is absorbed more rapidly than naproxen formulation.
Distribution: Highly protein-bound. It crosses the placental barrier and appears in milk.
Metabolism: Metabolized in the liver.
Excretion: Excreted in urine. Half-life is 10 to 20 hours.

Contraindications and precautions
Contraindicated in patients hypersensitive to drug and in those with asthma, rhinitis, or nasal polyps that is precipitated by aspirin or other NSAIDs. Use cautiously in elderly patients and those with a history of peptic ulcer disease or renal, CV, GI, or hepatic disease.

Interactions
Drug-drug. Acetaminophen, anti-inflammatories, gold compounds: Increases nephrotoxicity. Monitor renal function test results.
Anticoagulants, thrombolytics, such as coumadin derivatives, heparin, streptokinase, and urokinase: May potentiate anticoagulant effects. Monitor PT and INR.
Antihypertensives, diuretics: Decreases effects of these drugs. Using together may increase risk of nephrotoxicity. Avoid use together.
Anti-inflammatories, corticosteroids, corticotropin, salicylates: May cause increased GI adverse reactions, including ulceration and hemorrhage. Use together very cautiously.
Aspirin: May decrease the bioavailability of naproxen. Monitor patient for lack of effectiveness.
Aspirin, cefamandole, cefoperazone, dextran, dipyridamole, mezlocillin, parenteral carbenicillin, piperacillin, plicamycin, salicylates, sulfinpyrazone, ticarcillin, valproic acid, other anti-inflammatories: Increases risk of bleeding problems. Use together very cautiously.
Coumadin derivatives, nifedipine, phenytoin, verapamil: Increases risk of toxicity. Monitor patient closely.
Insulin, oral antidiabetics: May potentiate hypoglycemic effects. Monitor serum glucose level.
Lithium, methotrexate: May increase nephrotoxicity. Monitor renal function test results.
Drug-lifestyle. Alcohol use: Increases risk of GI toxicity. Discourage alcohol use.

Adverse reactions
CNS: headache, drowsiness, dizziness, vertigo, confusion.
CV: edema, palpitations.
EENT: visual disturbances, tinnitus, auditory disturbances.
GI: epigastric distress, occult blood loss, nausea, peptic ulceration, constipation, dyspepsia, heartburn, diarrhea, stomatitis, thirst.
GU: nephrotoxicity.
Hematologic: thrombocytopenia, eosinophilia, agranulocytosis, neutropenia, hemolysis.
Hepatic: liver impairment.
Respiratory: dyspnea.
Skin: pruritus, rash, urticaria, ecchymoses, diaphoresis, purpura.

Effects on lab test results
• May increase BUN, creatinine, ALT, AST, and potassium levels.
• May increase bleeding time and eosinophil count. May decrease neutrophil, granulocyte, and platelet counts.

Overdose and treatment
Signs and symptoms of overdose include drowsiness, heartburn, indigestion, nausea, and vomiting.
 To treat naproxen overdose, empty patient’s stomach immediately by inducing emesis with ipecac syrup or by performing gastric lavage. Administer activated charcoal via nasogastric tube. Provide symptomatic and supportive measures, including respiratory support and correction of fluid and electrolyte imbalances. Monitor laboratory parameters and vital signs closely. Hemodialysis is ineffective in removing naproxen.

Special considerations
• Keep in mind that 220 mg, 275 mg, and 550 mg of naproxen sodium equals 200 mg, 250 mg, and 500 mg of naproxen, respectively.
• Use naproxen sodium and naproxen oral suspension cautiously in patients restricting sodium intake. Naproxen oral suspension contains 0.34 mEq sodium per ml. Naproxen sodium 220 mg, 275 mg, and 550 mg contain 0.87 mEq, 1 mEq, and 2 mEq, respectively.
• Relief from inflammatory conditions usually begins within 2 weeks after beginning therapy with naproxen.
• Institute safety measures to prevent injury resulting from possible CNS effects.
• Naproxen may have a heart benefit, similar to aspirin, in preventing blood clotting. More studies have to be done to make clinical judgments.
• Monitor fluid balance. Watch for signs and symptoms of fluid retention, especially significant weight gain.
• Monitor liver function test results, renal function test results, CBC, and bleeding times during long-term therapy.
• Naproxen and its metabolites may interfere with urinary 5-hydroxyindoleacetic acid and 17-hydroxycorticosteroid determinations.
Breast-feeding patients
• Because both drugs appear in breast milk, avoid use in breast-feeding women.
Pediatric patients
• Safety of naproxen in children younger than age 2 hasn’t been established.
• Safety of naproxen sodium in children hasn’t been established.
Geriatric patients
• Patients older than age 60 are more sensitive to adverse effects (especially GI toxicity).
• Naproxen may cause fluid retention and edema, which may be significant in elderly patients, especially those with heart failure.

Patient education
• Warn patient not to take naproxen with OTC drugs.
• Teach patient signs and symptoms of possible adverse reactions and tell him to report them promptly.
• Instruct patient to check his weight every 2 to 3 days and to report any gain of 3 lb (1.4 kg) or more within 1 week.
• Instruct patient in safety measures; advise him to avoid activities that require alertness until CNS effects are known.
• Warn patient against combining naproxen with naproxen sodium because both drugs circulate in the blood as naproxen anion.
• Teach patient not to break or crush controlled-release or delayed-release tablets.
• Tell patient to take drug with food, milk, or antacids to avoid GI toxicity.

Reactions may be common, uncommon, life-threatening, or COMMON AND LIFE THREATENING.
◆ Canada only
◇ Unlabeled clinical use