Oral Acute musculoskeletal disorders, Dysmenorrhoea, Mild to moderate pain
Adult: As conventional tab/gastro-resistant tab/oral susp: Initially, 500 mg followed by 250 mg 6-8 hourly as necessary. Max: 1,250 mg on the 1st day then 1,000 mg thereafter. As extended-release tab: Initially, 1,000 mg once daily, may be adjusted to 1,500 mg once daily for a short period. Max: 1,000 mg daily. Elderly: Lowest effective dose for the shortest possible duration.
Oral Juvenile idiopathic arthritis
Child: >5 years 10 mg/kg daily in 2 divided doses 12 hourly. Max: 1,000 mg daily.
Adult: As conventional tab/gastro-resistant tab/oral susp: 500-1,000 mg daily as a single or in 2 divided doses. As effervescent tab: Initially, 250 mg twice daily, may be adjusted to 500-1,000 mg daily in 2 divided doses. As extended-release tab: 750-1,000 mg once daily, may be adjusted according to clinical response. Max: 1,000 mg daily. As delayed-release tab: 375 mg or 500 mg twice daily, may be adjusted according to clinical response. Use lowest effective dose for the shortest possible duration based on individual patient treatment goals. Elderly: Lowest effective dose for the shortest possible duration.
Oral Acute gout
Adult: As conventional tab/effervescent tab: Initially, 750 mg followed by 250 mg 8 hourly until the attack subsides. As extended-release tab: Initially, 1,000-1,500 mg followed by 1,000 mg once daily until the attack subsides. Elderly: Lowest effective dose for the shortest possible duration.
Special Patient Group
Patient with severe night time pain or morning stiffness, pain as predominant symptom in osteoarthritis, and who are switched to naproxen from high dose of another anti-rheumatic drug: As conventional tab/gastro-resistant tab/oral susp: Loading dose of 750 mg or 1,000 mg daily.
Renal Impairment
CrCl <30 mL/min or on dialysis: Contraindicated.
Hepatic Impairment
Severe: Contraindicated.
Administration
Should be taken with food.
Contraindications
Hypersensitivity. Patient with active or history of recurrent peptic ulcer, history of gastrointestinal bleeding or perforation related to previous NSAID therapy, chronic dyspepsia, severe heart failure, history of asthma, bronchospasm, nasal polyps, rhinitis, angioedema, or urticaria associated with aspirin or NSAID therapy. Treatment of peri-operative pain in the setting of CABG surgery. Renal (CrCl <30 mL/min) and severe hepatic impairment. Pregnancy (3rd trimester).
Special Precautions
Patient with or a history of bronchial asthma, inflammatory bowel disease (e.g. Crohn’s disease, ulcerative colitis), mild to moderate heart failure, fluid retention, ischaemic heart disease, peripheral arterial disease, cerebrovascular disease, coagulation disorders, risk factors for CV events (e.g. hyperlipidaemia, diabetes mellitus, smoking), cirrhosis, chronic alcoholic liver disease, dehydration, hypovolaemia. Debilitated patients. Mild to moderate renal and hepatic impairment. Elderly. Pregnancy (1st-2nd trimester) and lactation.
This drug may cause dizziness, drowsiness or blurred vision, if affected, do not drive or operate machinery.
MonitoringParameters
Monitor CBC, chemistry profile, renal and liver function. Blood pressure should be monitored during initiation of treatment and throughout the course of therapy.
Overdosage
Symptoms: Headache, nausea, vomiting, epigastric pain, indigestion, heartburn, gastrointestinal bleeding, lethargy, hypoprothrombinaemia, apnoea, metabolic acidosis. Rarely, diarrhoea, disorientation, excitation, drowsiness, dizziness, tinnitus, fainting, convulsions, hypertension, respiratory depression, coma, acute renal and liver damage. Management: Symptomatic and supportive treatment. Consider activated charcoal, emesis, osmotic cathartic, or gastric lavage within 1-4 hours of ingestion. Ensure good urine output. Administer IV diazepam for frequent or prolonged convulsions.
Drug Interactions
May increase the risk of bleeding with other NSAIDs or salicylates (e.g. aspirin), anticoagulants (e.g. warfarin), corticosteroids, SSRI. May decrease efficacy of antihypertensive agents (e.g. ß-blockers, ACE inhibitors, angiotensin II receptor antagonists). Increased risk of nephrotoxicity of ciclosporin and tacrolimus. May increase risk of haematological toxicity with zidovudine. Reduced natriuretic effects of diuretics (e.g. furosemide, thiazide diuretics). Increased plasma concentration and prolonged half-life with probenecid. May increase serum levels of lithium, digoxin, and methotrexate. May decrease the effects of mifepristone. Increased risk of myelosuppression, renal and gastrointestinal toxicity of pemetrexed. Delayed absorption rate with antacid, colestyramine, and sucralfate.
Food Interaction
Decreased rate of absorption with food.
Lab Interference
May result to false-positive aldosterone/renin ratio (ARR). May interfere with 5-hydroxyindoleacetic acid (5-HIAA) urinary assays. May cause a falsely elevated urinary 17-ketogenic steroid concentrations by interfering with the m-dinitrobenzene reagent in Porter-Silber test.
Action
Description: Naproxen, a propionic acid derivative, is a prototypical NSAID which reversibly inhibits the cyclooxygenase-1 and -2 (COX-1 and -2) enzymes, thus resulting in decreased formation of prostaglandin precursors. It has anti-inflammatory, analgesic and antipyretic activity, and can inhibit platelet aggregation. Onset: Analgesic: 30-60 minutes. Duration: Analgesic: <12 hours. Pharmacokinetics: Absorption: Readily absorbed from the gastrointestinal tract. Decreased absorption rate with food. Bioavailability: 95%. Time to peak plasma concentration: Conventional tab: Approx 1-2 hours (naproxen Na); Approx 2-4 hours (naproxen); Delayed-release tab: 4-6 hours (empty stomach); 12 hours (with food); 1-4 hours (oral susp). Distribution: Diffuses into synovial fluid. Crosses placenta and distributed into breast milk (small amounts). Volume of distribution: 0.16 L/kg. Plasma protein binding: >99% mainly to albumin. Metabolism: Extensively metabolised in the liver by CYP1A2 and CYP2C9 isoenzymes to inactive 6-O-desmethylnaproxen which undergoes further metabolism to its respective acylglucuronide conjugate metabolites. Excretion: Mainly via urine (approx 95%) as unchanged drug and metabolites; faeces (<5%). Elimination half-life: Approx 12-17 hours.
Chemical Structure
Naproxen Source: National Center for Biotechnology Information. PubChem Database. Naproxen, CID=156391, https://pubchem.ncbi.nlm.nih.gov/compound/Naproxen (accessed on Jan. 22, 2020)
Storage
Store between 15-30°C. Protect from light and heat.
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