Naproxen – Uses, Dosage & Side Effects

What is Naproxen?

Naproxen is a nonsteroidal anti-inflammatory drug (NSAID) widely used to relieve pain, reduce inflammation, and lower fever. It is available both over the counter and by prescription, depending on the dosage and country of use. Naproxen is one of the most commonly used analgesic and anti-inflammatory agents worldwide and belongs to the propionic acid class of NSAIDs.

Indications

Naproxen is indicated for a broad range of conditions, including:

• Osteoarthritis and rheumatoid arthritis: reduction of joint pain and swelling
• Dysmenorrhea: relief of menstrual cramps
• Acute gout attacks: management of acute gouty inflammation
• Soft tissue disorders: such as tendinitis, bursitis, and tennis elbow
• Headache and migraine
• Postoperative pain and other mild to moderate pain conditions
• Fever: short-term reduction of elevated body temperature

Mechanism of Action

Naproxen works by inhibiting the enzyme cyclooxygenase (COX), specifically both the COX-1 and COX-2 isoforms. These enzymes are responsible for the synthesis of prostaglandins – signaling molecules that mediate pain, inflammation, and fever. By blocking prostaglandin production, naproxen reduces the intensity of pain signals, dampens inflammatory responses, and lowers elevated body temperature. Compared to ibuprofen, naproxen has a longer half-life, which allows for twice-daily dosing in most cases.

Dosage and Administration

The standard adult dose of naproxen is 250 mg to 500 mg taken twice daily, depending on the indication and formulation. The maximum recommended daily dose is generally 1000–1250 mg. Naproxen should be taken with a full glass of water and preferably with food or milk to reduce the risk of gastrointestinal side effects. The lowest effective dose for the shortest possible duration is always recommended.

Special Patient Groups

• Elderly patients: increased risk of gastrointestinal complications and renal impairment – lower doses are advised
• Children and adolescents: use only under medical supervision
• Pregnancy: contraindicated in the third trimester; use in the first and second trimesters only under medical guidance

Side Effects

Like all NSAIDs, naproxen may cause side effects. Common side effects include:

• Gastrointestinal complaints: nausea, heartburn, stomach pain, and peptic ulcers
• Headache and dizziness
• Fluid retention (edema)
• Elevated blood pressure
• Renal impairment with prolonged use

Rare but serious adverse effects include gastrointestinal bleeding, cardiovascular events (e.g., heart attack, stroke), and severe allergic reactions. Co-administration of a proton pump inhibitor (PPI) is often recommended to protect the gastric mucosa, especially in at-risk patients.

Contraindications

Naproxen should not be used in patients with:

• Known hypersensitivity to naproxen or other NSAIDs
• Active peptic ulcers or gastrointestinal bleeding
• Severe renal, hepatic, or cardiac insufficiency
• Third trimester of pregnancy
• Concomitant use of anticoagulants – only under strict medical supervision

Drug Interactions

Naproxen may interact with several medications, including anticoagulants (e.g., warfarin), diuretics, ACE inhibitors, other NSAIDs, as well as lithium and methotrexate. Medical advice should always be sought before combining naproxen with other medications.

References

1. European Medicines Agency (EMA): Summary of Product Characteristics – Naproxen. Available at: https://www.ema.europa.eu
2. Brunton L.L., Knollmann B.C. (eds.): Goodman & Gilman's The Pharmacological Basis of Therapeutics. 14th edition. McGraw-Hill, New York, 2023.
3. World Health Organization (WHO): WHO Model Formulary 2023 – Analgesics and NSAIDs. Available at: https://www.who.int