Arnex, a propionic acid derivative, is a prototypical NSAID. It reversibly inhibits the cyclooxygenase-1 and -2 (COX-1 and -2) enzymes, thus resulting in reduced synthesis of prostaglandin precursors. It can inhibit platelet aggregation, has anti-inflammatory, analgesic and antipyretic actions.
Arnex is used for the relief of symptoms of rheumatoid arthritis, both of acute flares and long term management of the disease. It is also used in the diseases of rheumatoid osteoarthritis (degenerative arthritis), ankylosing spondylitis, juvenile rheumatoid arthritis, tendinitis, brusitis, acute gout, acute musculoskeletal disorders (such as sprains, direct trauma and fibrositis), migraine and dysmenorrhoea.
Arnex is also used to associated treatment for these conditions: Acute Gouty Arthritis, Acute Migraine, Ankylosing Spondylitis (AS), Arthritis, Backache, Bursitis, Extra-Articular Rheumatism, Fever, Flu caused by Influenza, Headache, Juvenile Idiopathic Arthritis (JIA), Menstrual Distress (Dysmenorrhea), Migraine, Muscle Spasms, Nasal Congestion, Osteoarthritis (OA), Pain, Post-traumatic pain, Postoperative pain, Primary Dysmenorrhoea, Rheumatoid Arthritis, Rheumatoid Arthritis, Juvenile, Seasonal Allergic Rhinitis, Sinusitis, Tendinitis, Toothache
|Naproxen Other Names||(S)-Naproxen, Naprolag, Naproxen, Naproxène, Naproxeno, Naproxenum|
Naproxen is highly protein bound with >99% of the drug bound to albumin at therapeutic levels.
|Therapeutic Class||Drugs for Osteoarthritis, Drugs used for Rheumatoid Arthritis, Non-steroidal Anti-inflammatory Drugs (NSAIDs)|
|Manufacturer||Silva Pharmaceuticals Ltd|
|Last Updated:||June 23, 2021 at 11:23 am|
Tablet & Suppository (Adult)-
- Rheumatic disorders: The usual initial dose of naproxen is 250 mg twice daily adjusted to 500 mg to 1000 mg daily in 2 divided doses.
- Juvenile arthritis: A dose of 10 mg/kg body weight daily in 2 divided doses is used for children over 5 years of age.
- Acute gout: An initial dose of 750 mg followed by 250 mg every 8 hours.
- Dysmenorrhoea: 500 mg may be given initially followed by 250 mg in every 6-8 hours.
Syrup (Children over 5 years)-
- In juvenile arthritis: The usual dosage of Arnex is 10 mg/kg/day taken in two doses at 12-hour intervals is recommended.
Gel: Arnex gel is to be applied 2-6 times a day as required and is not recommended for use in children.
Gastro-intestinal discomfort: nausea, diarrhoea and occasionally bleeding and ulceration.
Hypersensitivity reactions: notably with bronchospasm, rashes and angioedema.
CNS side effect: drowsiness, headache, fluid retention, vertigo, hearing disturbances such as tinnitus, photosensitivity.
A few instances of jaundice, impairment of renal function, thrombocytopenia, and agranulocytosis have been reported.
Arnex should be used with caution in patients with cardiac, hepatic and renal impairment, coagulation defect, and previous history of gastro-intestinal ulceration. The drug is contraindicated in patients with a history of hypersensitivity to aspirin or any other NSAID - which includes those in whom attacks of asthma, angioedema, urticaria or rhinitis have been precipitated by aspirin or any other NSAID.
Antacid: The absorption of naproxen can be altered by antacids.
Aspirin: Plasma concentration of Arnex can be reduced when aspirin is given concomitantly, this appeared to be due to increased exeretion of naproxen.
Diuretics: Arnex diminish the effect of frusemide.
Probenecid: It increase the plasma concentration of Arnex.
- Take with food. Food reduces GI irritation.
Volume of Distribution
Arnex has a volume of distribution of 0.16 L/kg.
The elimination half-life of naproxen is reported to be 12-17 hours.
Arnex is cleared at a rate of 0.13 mL/min/kg.
Pregnancy & Breastfeeding use
There are no well controlled studies in pregnant women. The drug should not be used during pregnancy unless clearly needed. Because of the possible adverse effects of prostaglandin inhibiting drugs on neonates, use in nursing mothers must be avoided.
Arnex suppository in contraindicated in children under 12 years of age. The suppository is contraindicated also in patients with any inflammatory lesions of rectum or anus and in patients with recent history of rectal or anal bleeding.
Significant overdosage of the drug may be characterized by drowsiness, heartburn, indigestion, and nausea or vomiting. It is not known what dose of the drug would be life threatening.
Tablet: Protect from light and store below 30° C temperature in a dry place.
Suppository: Store below 25°C temperature.
Gel: Store in a cool and dry place protected from light.