Naproxen for Period Pain: Why It Works and How to Use It
Why naproxen 500mg twice daily is often the best NSAID for dysmenorrhoea — dose, timing, and how to get it.
Part of the Access Doctor period pain guide.
Key fact: Naproxen’s long half-life (12–17 hours) means a 500mg twice-daily prescription dose provides sustained prostaglandin suppression throughout the day with just two tablets. For period pain — where prostaglandins are elevated for 24–48 hours — this makes naproxen more convenient and often more effective than shorter-acting ibuprofen.
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 →How Naproxen Relieves Period Pain
Period pain is caused by prostaglandins — inflammatory molecules produced by the uterine lining as progesterone falls at the end of the cycle. Prostaglandins trigger intense uterine contractions and reduce blood flow to the uterine muscle, causing ischaemic cramping. Naproxen is a non-selective COX-1/COX-2 inhibitor: it blocks both cyclooxygenase enzymes that produce prostaglandins, directly reducing the concentration of the molecules driving the pain.
The critical insight for period pain is timing: naproxen is most effective when taken at the very first sign of pain or bleeding, before prostaglandin levels have peaked. Waiting until pain is severe means fighting an already-established inflammatory process rather than preventing it from escalating.
Correct Dose and Timing
| Formulation | Dose | Frequency | Duration |
|---|---|---|---|
| OTC naproxen sodium 250mg | 500mg (2 tablets) as first dose, then 250mg every 6–8h | Max 3 doses/day | Use for 2–3 days |
| Prescription naproxen 500mg | 500mg (1 tablet) | Twice daily (morning and evening) | Use for 2–3 painful days |
1
Take the first 500mg at the very first sign of pain or bleeding
Do not wait until pain is severe. Many women take the first dose when bleeding starts, even before significant pain develops, to keep prostaglandin levels low from the outset.
2
Take with food or milk
Naproxen is a COX-1 inhibitor and reduces gastroprotective prostaglandins in the stomach. Taking with food significantly reduces GI side effects.
3
Take the second 500mg 8–12 hours later
Naproxen’s long half-life means twice-daily dosing maintains therapeutic blood levels throughout the day — unlike ibuprofen which needs 3–4 doses.
4
Continue for 2–3 days
Continue through the painful days of your period. Stop once pain has resolved. Do not take beyond 5 days without medical guidance.
Combination tip: Naproxen and paracetamol (1g every 4–6h) are safe to combine and work by different mechanisms. Adding paracetamol provides additional central analgesia on top of naproxen’s anti-inflammatory effect. Never combine naproxen with another NSAID (e.g. ibuprofen).
Naproxen vs Ibuprofen for Period Pain
| Feature | Naproxen 500mg | Ibuprofen 600mg |
|---|---|---|
| Half-life | 12–17 hours | ~2 hours |
| Doses per day | 2 (morning and evening) | 3 (every 6–8 hours) |
| Onset | 30–60 minutes | 20–30 minutes (slightly faster) |
| Duration of effect | 8–12 hours per dose | 4–6 hours per dose |
| Convenience | Higher — fewer doses, less chance of missing one | More doses required |
| Preferred for | All-day sustained relief; women who want fewer doses | Quick initial relief; women sensitive to naproxen |
In clinical practice, many prescribers prefer naproxen for period pain specifically because the twice-daily regimen is less likely to result in missed doses during a busy day — and missed doses during the first 24–48 hours allow prostaglandin levels to rebound. Both are clinically appropriate first-line options per NICE.
Side Effects and Precautions
- GI discomfort, nausea, heartburn — most common; significantly reduced by taking with food. If persistent, a PPI (omeprazole) can be co-prescribed.
- Headache and dizziness — mild; usually resolves with regular use
- Fluid retention — can cause mild ankle swelling with regular use
- Raised blood pressure — important for those already hypertensive; monitor if using regularly
Seek urgent medical advice if you develop black/tarry stools, vomiting blood, severe abdominal pain, or sudden worsening of breathlessness while taking naproxen.
Who Cannot Take Naproxen
- Peptic ulcer disease or GI bleeding history — contraindicated without PPI cover and specialist advice
- Significant kidney impairment (eGFR <30) — NSAIDs reduce renal blood flow
- Aspirin-sensitive asthma / NSAID hypersensitivity — cross-reactivity; contraindicated
- Third trimester of pregnancy — risk of premature ductus arteriosus closure; use paracetamol instead
- Severe heart failure
- Taking anticoagulants (warfarin, rivaroxaban) — increased bleeding risk; requires prescriber assessment
Frequently Asked Questions
Why is naproxen often the best NSAID for period pain?
Naproxen's long half-life (12–17 hours) allows a 500mg twice-daily prescription dose to maintain sustained prostaglandin suppression all day with just two tablets — fewer missed doses, more consistent relief than shorter-acting ibuprofen.
What is the correct dose of naproxen for period pain?
Prescription: 500mg twice daily (morning and evening) with food. Start at the very first sign of pain or bleeding. Continue for 2–3 painful days. OTC: 500mg first dose, then 250mg every 6–8 hours.
Can I take naproxen and paracetamol together?
Yes — safe combination. They work by different mechanisms: naproxen reduces prostaglandins (peripheral anti-inflammatory); paracetamol adds central analgesia. Never combine naproxen with another NSAID.
When should I take naproxen for period pain?
At the very first sign of pain or bleeding — do not wait until pain is severe. Taking naproxen before prostaglandin levels peak significantly improves effectiveness.
Who cannot take naproxen?
Peptic ulcer disease, significant kidney impairment (eGFR <30), aspirin-sensitive asthma, third trimester pregnancy, severe heart failure, or concurrent anticoagulants without prescriber assessment.
Can I get naproxen for period pain online?
Yes. Access Doctor prescribers can assess and prescribe naproxen 500mg online without a GP appointment. Prescriptions issued same day where appropriate, with next-working-day delivery.
References
- National Institute for Health and Care Excellence (NICE). Heavy menstrual bleeding: assessment and management (NG88). 2018 (updated 2023). nice.org.uk/guidance/ng88
- Marjoribanks J et al. Nonsteroidal anti-inflammatory drugs for dysmenorrhoea. Cochrane Database Syst Rev. 2015. PubMed: 26224322
- NHS. Naproxen. nhs.uk/medicines/naproxen
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.