Waikakul 1995.

Methods	RCT; participants were randomly allocated to 2 groups according to the last 2 digits of their hospital numbers Follow‐up time: 6 weeks. Outcome measurements at baseline and after 1 and 6 weeks
Participants	Population and setting: 72 hospital patients with non‐surgical low back pain, 20 men, 52 women Inclusion criteria: non‐surgical low back pain including disc syndrome, spondylosis, mild spondylolisthesis, spinal stenosis, and postural back pain, aged 15 years and older Exclusion criteria: presence of digestive, haematological, hepatic, and renal disorders, hypersensitivity to proprionic acid derivatives, long‐term administration of steroids, indication for surgery
Interventions	NSAID (i): Loxoprofen 60 mg t.i.d., 6 weeks (N = 37) NSAID (ii): naproxen 250 mg t.i.d., 6 weeks (N = 35)
Outcomes	Therapeutic results according to criteria of the Japanese orthopaedic Academic Society, adverse events
Notes	1. Duration of LBP not clear 2. We were unable to find contact details to ask for clarification (21 October 2019)