Naproxen UK Guide: Dosage, Uses, Side Effects and Interactions
All indications, correct doses, timing, side effects, drug interactions, contraindications and how to get it online.
Part of the Access Doctor Pain guide. For naproxen specifically for period pain, see Naproxen for Period Pain.
At a glance: Naproxen is an NSAID that inhibits COX-1 and COX-2 enzymes, reducing prostaglandin synthesis and thereby reducing pain and inflammation. Its long half-life (12–17 hours) makes it particularly convenient — most conditions require only twice-daily dosing. Available OTC at 250mg and on prescription at 500mg.
Get Prescription Pain Relief Online
Access Doctor GPhC-registered pharmacist independent prescribers can prescribe naproxen 500mg and ibuprofen 600mg for period pain online. No GP appointment needed. Next-working-day delivery.
Start Consultation →What Is Naproxen?
Naproxen is a non-selective non-steroidal anti-inflammatory drug (NSAID) that inhibits both COX-1 and COX-2 cyclooxygenase enzymes. By blocking these enzymes, naproxen reduces the synthesis of prostaglandins and thromboxanes — inflammatory mediators that cause pain, swelling, fever, and (in the uterus) dysmenorrhoea cramping.
Naproxen has been in clinical use since the 1970s and has an extensive safety record at recommended doses. It is available OTC as naproxen sodium 250mg tablets in the UK, and on prescription as naproxen 500mg tablets. Both formulations are identical in mechanism; the sodium salt in the OTC preparation is absorbed slightly faster.
What Is Naproxen Used For?
- Period pain (dysmenorrhoea) — NICE first-line; 500mg twice daily prescription dose is particularly effective; see Naproxen for Period Pain
- Musculoskeletal pain — back pain, sprains, strains, soft tissue injuries
- Osteoarthritis — for acute flares and ongoing joint pain
- Rheumatoid arthritis — anti-inflammatory management of joint inflammation
- Gout — effective for acute gout attacks (750mg initially, then 250mg every 8h)
- Ankylosing spondylitis
- Post-operative and procedural pain
- Dental pain
Dosage
| Formulation | Indication | Dose | Max daily dose |
|---|---|---|---|
| OTC naproxen sodium 250mg | Mild-moderate pain | 500mg first dose, then 250mg every 6–8h | 750mg/day (after first dose) |
| Prescription naproxen 500mg | Period pain, musculoskeletal | 500mg twice daily | 1,000mg/day |
| Prescription naproxen 500mg | Inflammatory arthritis | 500–750mg twice daily (as directed) | 1,250mg/day initially; 1,000mg/day ongoing |
| Prescription naproxen 500mg | Acute gout | 750mg immediately, then 250mg every 8h | 1,250mg on day 1 |
How to Take Naproxen
- Always take with food or milk — significantly reduces GI side effects
- Swallow whole with a full glass of water
- For period pain: start at the first sign of bleeding or pain; do not wait
- Do not exceed the stated dose
- Do not combine with another NSAID (ibuprofen, aspirin analgesic doses, diclofenac)
- Avoid alcohol — increases GI side effect risk
Side Effects
Common (up to 1 in 10)
- Nausea, heartburn, indigestion, stomach discomfort
- Headache, dizziness
- Fluid retention (mild ankle swelling)
Uncommon but important
- Raised blood pressure — monitor with regular use
- Impaired kidney function with prolonged use
- Skin reactions (rash)
Seek urgent medical advice for: black or tarry stools, vomiting blood, severe abdominal pain (possible GI bleeding), chest pain or shortness of breath (cardiovascular), or significantly reduced urine output (renal impairment).
Contraindications
- Active peptic ulcer disease or GI bleeding history — unless with gastroprotective PPI cover under prescriber guidance
- Significant renal impairment (eGFR <30) — NSAIDs reduce renal blood flow
- Aspirin-sensitive asthma / NSAID hypersensitivity
- Third trimester of pregnancy — risk of premature closure of ductus arteriosus
- Severe heart failure
- Severe hepatic impairment
Use with caution and prescriber assessment: age over 65; cardiovascular disease; anticoagulant use; concurrent corticosteroids or SSRIs; mild-to-moderate renal impairment; first and second trimester pregnancy.
Key Drug Interactions
| Drug / class | Interaction | Management |
|---|---|---|
| Anticoagulants (warfarin, rivaroxaban) | Increased bleeding risk | Avoid or use with close INR monitoring; prescriber assessment |
| Other NSAIDs / aspirin | Additive GI and cardiovascular risk; no added benefit | Do not combine |
| SSRIs (fluoxetine, sertraline) | Increased GI bleeding risk | Use PPI cover; prescriber awareness |
| ACE inhibitors / ARBs | Reduced antihypertensive effect; increased renal risk | Monitor blood pressure and renal function |
| Diuretics | Reduced diuretic effect; increased renal risk | Monitor; avoid dehydration |
| Lithium | Naproxen raises lithium levels | Avoid; use paracetamol instead |
| Methotrexate | Reduced methotrexate clearance; toxicity risk | Avoid NSAIDs with methotrexate without specialist guidance |
Naproxen vs Ibuprofen: Key Differences
| Feature | Naproxen | Ibuprofen |
|---|---|---|
| Half-life | 12–17 hours | ~2 hours |
| Dosing frequency | Twice daily | Three times daily (at 600mg) |
| OTC availability | 250mg tablets | 200mg and 400mg tablets |
| Onset | 30–60 min | 20–30 min (slightly faster) |
| Best advantage | Sustained all-day relief; fewer doses | Faster onset; more flexible dosing |
Frequently Asked Questions
What is naproxen used for?
Period pain, musculoskeletal pain, osteoarthritis, rheumatoid arthritis, gout, ankylosing spondylitis, post-operative pain, and dental pain.
What is the correct dose of naproxen?
OTC: 500mg first dose then 250mg every 6–8h (max 750mg/day after first dose). Prescription: 500mg twice daily for most indications including period pain.
How long does naproxen take to work?
30–60 minutes to begin working; peak effect at 2–4 hours; sustained relief for 8–12 hours per dose.
What are the most common side effects of naproxen?
GI symptoms (nausea, heartburn, indigestion) — significantly reduced by taking with food. Headache, dizziness, fluid retention are less common.
Who cannot take naproxen?
Active peptic ulcer, significant kidney impairment (eGFR <30), aspirin-sensitive asthma, third trimester pregnancy, severe heart failure.
Can I take naproxen with ibuprofen?
No. Both are NSAIDs — combining increases risk with no added benefit. Naproxen can safely be combined with paracetamol.
References
- National Institute for Health and Care Excellence (NICE). Heavy menstrual bleeding: assessment and management (NG88). 2018 (updated 2023). nice.org.uk/guidance/ng88
- NHS. Naproxen. nhs.uk/medicines/naproxen
- Electronic Medicines Compendium. Naproxen 500mg tablets: Summary of Product Characteristics. medicines.org.uk/emc
Medical disclaimer: This article is for informational purposes only. Period pain can be a symptom of an underlying condition requiring assessment. In an emergency call 999.