Naproxen

A long-acting anti-inflammatory painkiller explained with chemistry, biology, and clinical science.

What is Naproxen?

Naproxen is a non-steroidal anti-inflammatory drug (NSAID) used to treat pain, fever, and inflammation. It is known for its long duration of action, which allows less frequent dosing compared to some other NSAIDs.

Because of its sustained effect, naproxen is commonly prescribed for chronic inflammatory conditions like arthritis.

History & Development

Naproxen was developed in the 1970s and gained popularity due to its strong anti-inflammatory action and longer half-life, making it suitable for twice-daily dosing.

Chemical Structure & Properties

• IUPAC name: (S)-6-methoxy-α-methyl-2-naphthaleneacetic acid
• Molecular formula: C₁₄H₁₄O₃
• Molar mass: 230.26 g/mol
• Functional groups: Carboxylic acid, aromatic naphthalene ring

The naphthalene ring increases lipophilicity, contributing to strong binding with COX enzymes and prolonged action.

Mechanism of Action

Naproxen inhibits cyclooxygenase enzymes (COX-1 and COX-2), reducing the formation of prostaglandins responsible for pain, inflammation, and fever.

• ↓ Prostaglandins → reduced pain
• ↓ Inflammation mediators → reduced swelling
• ↓ Fever response

Pharmacokinetics

• Absorption: Well absorbed orally
• Peak plasma time: 2–4 hours
• Protein binding: ~99%
• Half-life: 12–17 hours
• Metabolism: Liver
• Excretion: Urine

Medical Uses

• Osteoarthritis and rheumatoid arthritis
• Muscle and joint pain
• Back pain
• Menstrual pain
• Gout attacks

Dosage Guidelines

Adults: 250–500 mg twice daily

Maximum daily dose: 1000 mg

⚠️ Always take with food to reduce stomach irritation.

Side Effects

• Indigestion
• Stomach pain
• Nausea
• Dizziness

Serious Risks & Warnings

• Gastric ulcers and bleeding
• Kidney impairment
• Cardiovascular risk (long-term use)

Drug Interactions

• Other NSAIDs
• Blood thinners
• Diuretics
• Alcohol

Naproxen vs Diclofenac

Naproxen lasts longer and requires fewer doses, while diclofenac may provide faster relief for acute pain.

Frequently Asked Questions

Is naproxen stronger than ibuprofen? – Duration is longer, potency similar.

Can it be taken daily? – Only under medical supervision.

Is naproxen an antibiotic? – No.

Does it reduce swelling? – Yes.

⚠️ Educational content only. Not a substitute for professional medical advice.