This study will evaluate whether treatment with Naproxen 500 mg twice daily is superior to placebo for the improvement of leg pain in patients with sciatica. Half of patients will receive Naproxen while the other half will receive placebo.

Sciatica is an established term for pain radiating from the lower back or buttock into the leg, commonly caused by a disc herniation. Given their analgesic and anti-inflammatory mechanisms of action, NSAIDs (Non-steroidal anti-inflammatory drugs) have been, and are still being regarded as standard therapy for sciatica.

However, very few randomised controlled trials of NSAIDs have been undertaken in sciatica, and no study has showed clinically meaningful effects as compared to placebo.

Since NSAIDs involve the risk of serious gastrointestinal, vascular and renal side effects there is a strong need to clarify their potential beneficial effects in sciatica.

Inclusion criteria:

• Age ≥ 18 years
• Radiating pain below the knee with a severity score of ≥4 on a 0-10 (NRS) in the previous 24 hours
• Signs of nerve root/spinal nerve involvement as indicated by at least one of the following features; myotomal weakness, dermatomal sensory disturbances (e.g. sensory loss, self-reported tingling/numbness), diminished reflexes, radiating pain exacerbation by SLR

Exclusion criteria:

• Not able to read or speak Norwegian.
• Unlikely to adhere to treatment and/ or complete follow-up (e.g ongoing serious psychiatric disease, drug abuse, plans to move)
• Sciatica of known cause other than disc herniation or degenerative stenosis.
• Neurogenic claudication, i.e. pain in the legs on walking or standing that resolves with sitting down or lumbar flexion.
• Symptoms indicating immediate surgery: cauda equina syndrome or a progressive large paresis.
• Women who attempt to conceive, are pregnant or breastfeeding.
• Previous episodes of asthma, urticaria or allergic-type reactions after taking aspirin or other NSAIDs.
• Active or history of peptic ulceration, gastrointestinal bleeding, or perforation.
• Use of drugs known to increase upper gastrointestinal adverse events in combination with Naproxen: anticoagulants, aspirin (acetyl salicylic acid), serotonin reuptake inhibitors and systemic corticosteroids.
• Hepatic enzyme (ASAT/ALAT) values above 1,5 x upper limit of normal (ULN)
• Renal function tests (creatinin/eGFR) outside normal range
• Congestive heart failure, established ischaemic heart disease, peripheral arterial disease, and/or cerebrovascular disease.
• Known hypersensitivity to Naproxen or any of the excipients (lactose, maize starch, povidone, sodium starch glycolate, talcum, magnesium stearate, polysorbate 80)
• Ongoing treatment with aspirin, systemic corticosteroids, diuretics, ACE-inhibitors, lithium and anticoagulants
• Scheduled for spinal surgery prior to end of study
• Reservation against intake of gelatine (the capsules contains gelatine, which among other things is produced by ingredients from pigs)