Naproxen

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DRUGS
Naproxen

Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) that possesses antipyretic and analgesic properties. The anti-inflammatory effects of naproxen result from the peripheral inhibition of prostaglandin synthesis secondary to inhibition of the enzyme cyclooxygenase. Prostaglandins sensitize pain receptors, and their inhibition is believed to be responsible for the analgesic effects.

Introduction

Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) that possesses antipyretic and analgesic properties. The anti-inflammatory effects of naproxen result from the peripheral inhibition of prostaglandin synthesis secondary to inhibition of the enzyme cyclooxygenase. Prostaglandins sensitize pain receptors, and their inhibition is believed to be responsible for the analgesic effects.

Pharmacological Class: NSAID 

Indications

  • Acute gout
  • Dysmenorrhoea
  • Fever
  • Headache
  • Migraine
  • Musculoskeletal disorders
  • Pain
  • Rheumatoid arthritis
  • Rheumatic disorders

Pharamcological Action

Naproxen is a phenylpropionic acid derivative having analgesic, anti-inflammatory and antipyretic activities. Such activities are thought to be mediated via inhibition of the enzyme complex prostaglandin synthetase with consequent reduction in the synthesis of prostaglandins from arachidonic acid.

Dosage

Adult dose for

  • Rheumatoid arthritis, osteoarthritis & ankylosing spondylitis: 500-1000 mg orally, twice daily
  • Maintenance treatment: 500 mg orally, twice daily
  • Dysmenorrhoea & other indications: 500 mg orally initially, followed by 250 mg, once daily

Pediatric dose for

  • Juvenile rheumatoid arthritis: 10 mg/kg/day orally in 2 divided doses at 12 hours intervals

Pharmacokinetics

Oral absorption of Naproxen is found to be 100%. Volume of distribution is 0.9 l/kg and plasma protein binding is > 99%. Presystemic metabolism is noted to be 2.5% ±2.5 and metabolism is reported to occur extensively by liver. Renal excretion accounts for 97.5-99% and plasma half life is 12-17 hours.

Contraindications

  • In patients who have previously shown hypersensitivity reactions (e.g. asthma, rhinitis, angioedema or urticaria) in response to ibuprofen, aspirin or other NSAIDs
  • Severe hepatic, renal and cardiac failure
  • During last trimester of pregnancy
  • Active or previous acute peptic ulcer

Drug Interactions

  • Reduces antihypertensive activity of bisoprolol by renal prostaglandin synthesis inhibition
  • Piperazine ring of ciprofloxacin inhibits the binding of gamma-aminobutyric acid (GABA) to brain receptors and naproxen synergistically adds to this effect, thus increases the risk of central nervous system (CNS) stimulation and convulsion
  • Diminishes the diuretic effect of furosemide
  • Displaces phenytoin from protein binding sites

Side effects

Common (affecting between 1 in10 to 1 in 100)

  • Dizziness
  • Vertigo
  • Headache
  • Drowsiness
  • Nausea
  • Constipation
  • Abdominal pain

Uncommon (affecting 1 in 100 to 1 in 1000)

  • Visual disorders
  • Stomatitis
  • Jaundice
  • Dyspepsia
  • Malaise
  • Depression
  • Heart burn

Very rare (affecting less than 1 in 10,000)

  • Increased intracranial pressure
  • Pseudoporphyria
  • Leukocytoclastic vasculitis
  • Allergic Pneumonitis
  • Photodermatitis
  • Reversible Keratopathy

Precautions

  • Should be used with caution in patients with intrinsic coagulation defects and on anticoagulant therapy
  • May lead to new hypertension or worsening of existing hypertension
  • Should be used with caution in patients with other conditions predisposing to fluid retention
  • Should be used with extra care in the presence of existing controlled infection

Clinic Evidence

  • Naproxen effectively relieves pain in patients with mild to moderate osteoarthritis (OA) of the knee. It provides more effective pain relief for most variables compared with placebo, and for night pain compared with ibuprofen. Naproxen shows good efficacy, safety and tolerability.1
  • Naproxen is effective in treating pain and associated symptoms of primary or secondary dysmenorrhoea, and decreases excessive blood loss in patients with menorrhagia. The adverse effect profile of naproxen is well established, particularly compared with many newer NSAIDs, and the drug is well tolerated. Thus, the efficacy and tolerability of naproxen have been clearly established over many years of clinical use. Therefore, it can be considered as a first-line treatment for rheumatic diseases and various pain states.2

References

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