What Is Naproxen? Uses, Drug Class & How It Works

Part of the Access Doctor pain guide. This is the what-is & how-it-works guide. For doses, contraindications and how to get naproxen online, see naproxen for pain relief: doses & prescription.

What Is Naproxen Used For?

Naproxen is used mainly for inflammatory and musculoskeletal pain — conditions where prostaglandins are actively driving swelling and sensitising pain receptors. Common uses include:

• Sprains and strains and other soft-tissue injuries
• Back pain and musculoskeletal pain
• Osteoarthritis and rheumatoid arthritis
• Acute gout (NICE first-line NSAID)
• Period pain (dysmenorrhoea)
• Some migraines and headaches where an NSAID is appropriate

It's most useful where inflammation is part of the problem — for purely central or non-inflammatory pain, paracetamol may be enough. For full dosing and who can take it, see the naproxen doses & prescribing guide.

Drug Class: What Type of Medicine Is Naproxen?

Naproxen belongs to two classification categories:

• Non-steroidal anti-inflammatory drug (NSAID) — the broader class; distinguishes it from steroidal anti-inflammatories (corticosteroids) and from non-anti-inflammatory analgesics like paracetamol.
• Propionic acid derivative — the chemical subclass within NSAIDs; naproxen and ibuprofen are both propionic acid NSAIDs, which is why they share the same basic mechanism but differ in potency, half-life and dosing frequency.

Other NSAIDs by subclass: diclofenac is a phenylacetic acid derivative; aspirin is a salicylate; celecoxib (COX-2 selective) is a sulfonamide.

How It Works: COX Inhibition

To understand how naproxen works, it helps to know what prostaglandins do — because reducing them is exactly what naproxen does. When tissue is injured, infected or inflamed, the body produces prostaglandins, which:

• sensitise peripheral pain receptors (nociceptors), amplifying pain;
• cause vasodilation and increased vascular permeability — the redness and swelling of inflammation;
• act on the hypothalamus to raise body temperature (fever);
• protect the stomach lining by stimulating mucus secretion (relevant to NSAID safety).

Prostaglandin production is catalysed by two enzymes: COX-1 and COX-2. Naproxen inhibits both, cutting prostaglandin levels throughout the body. The result: sensitised pain receptors calm down, the inflammatory cascade is dampened, and fever reduces. Naproxen isn't just masking pain — it reduces the biological processes causing it.

COX-1 vs COX-2: Why It Matters

Naproxen inhibits both non-selectively — which is why it delivers the anti-inflammatory benefit (COX-2) but also the GI side effects (COX-1), and why a PPI is co-prescribed to compensate for reduced gastric protection.

Naproxen vs Ibuprofen

Both are propionic acid NSAIDs with the same mechanism, but their pharmacokinetics differ in ways that matter clinically:

Naproxen's long half-life means twice-daily dosing maintains steady anti-inflammatory levels — useful for conditions needing sustained effect like arthritis or gout. Ibuprofen acts faster but wears off sooner. See the full NSAIDs comparison.

Naproxen vs Paracetamol

Both relieve pain, but by entirely different mechanisms. Paracetamol acts centrally, changing how the brain perceives pain; it doesn't meaningfully reduce peripheral prostaglandins, so it doesn't treat inflammation at the site of injury. Naproxen acts at the source — reducing the prostaglandins that cause swelling and sensitise local pain receptors. For a sprained ankle, inflamed joint or gout attack, that mechanistic difference means naproxen usually works better.

Crucially, paracetamol and naproxen are safe to take together — different pathways, and the combination often relieves pain better than either alone. Never combine naproxen with ibuprofen or another NSAID.