Innes 1998.

Methods	RCT; double‐blind; multicentre. Randomised according to computer‐generated random allocation table, exact procedure not described. Follow‐up time: 7 to 9 days
Participants	Population: 122 emergency department participants with acute LBP, 26 women, 96 men. Mean age (SD), 34.5 (10), range 19 to 62 years Setting: 6 university and community hospital emergency departments in Canada Inclusion criteria: acute musculoskeletal low back pain (moderate/severe), onset within the previous 72 hours, age 18 to 60 years, weight > 50 kg, well enough for discharge within 4 hours, requirement of oral analgesics Exclusion criteria: treatment with investigational drug in previous 4 weeks; adverse events due to NSAIDs; hypersensitivity to analgesics, antipyretics, or NSAIDs; anti‐coagulants use within 4 weeks, concurrent treatment with other medications influencing pain intensity evaluations; active peptic ulcer within 6 months; anticoagulant use; conditions requiring treatment beyond analgesics; pregnancy or breastfeeding; alcohol or drug abuse; chronic or recurrent LBP or neurologic cause; interfering co‐existing injury or illness
Interventions	NSAID (i): Dose 1 to 4 per day: ketorolac tromethamine 10 mg (1 capsule) + placebo (1 capsule), every 4 to 6 hours as needed, up to 4 doses per 24 hours. Dose 5 and 6 per day, if required: acetaminophen 650 mg per dose (2 capsules); up to 7 days (N = 62). Reference treatment (ii): Dose 1 to 4 per day: acetaminophen 300 mg + codeine 30 mg per capsule (2 capsules), every 4 to 6 hours as needed. Dose 5 and 6 per day, if required: acetaminophen 650 mg per dose (2 capsules); up to 7 days (N = 60)
Outcomes	Pain mean changed score (SD), 100‐mm VAS, after 6 hours: (i, N = 55) ‐6.4 (17); (ii, N = 58) ‐5.4 (16), no significant differences % participants reporting 'a lot/complete' pain relief after 4 days: (i) 53%; (ii) 55%, no significant differences % participants reporting 'no/mild' impairment after 4 days: (i) 67%; (ii) 62%, no significant differences Adverse events: (i) 21 participants (0 withdrew); (ii) 38 participants (7 withdrew)
Funding	Study funded by Hoffmann‐La Roche of Canada (developer of Toradol = ketorolac tromethamine).
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomisation code
Allocation concealment (selection bias)	Unclear risk	Exact procedure not described
Blinding of participants and personnel (performance bias) All outcomes ‐ participants	Low risk	All drugs were prepared in identical capsules to preserve double‐blinding.
Blinding of participants and personnel (performance bias) All outcomes ‐ careproviders	Low risk	All drugs were prepared in identical capsules to preserve double‐blinding.
Blinding of outcome assessment (detection bias) All outcomes ‐ outcome assessors	Low risk	A blinded consultant entered all data and performed statistical analyses.
Incomplete outcome data (attrition bias) All outcomes ‐ dropouts	Low risk	Dropout rate: 18.9% (23/122 withdrew) 16 (10 (i) and 6 (ii)) withdrew prematurely because of analgesic inefficacy, 7 (ii) withdrew because of side effects
Incomplete outcome data (attrition bias) All outcomes ‐ ITT analysis	Unclear risk	Not mentioned
Selective reporting (reporting bias)	Unclear risk	Unclear if pain relief and impairment was also measured after 7 days; it was not mentioned. Study protocol locally approved, not registered.
Similarity at baseline characteristics	Low risk	Baseline characteristics similar
Co‐interventions avoided or similar	Unclear risk	Drug were packaged in blister cards that separated each day's drug supply into six doses labelled 1 to 6. Each 'dose' consisted of two capsules.
Compliance acceptable	Unclear risk	Not mentioned if blister cards with used/unused medication were collected. Participants were asked to record all medication intake in their study diary.
Timing outcome assessments similar	Low risk	Timing similar
Other bias	Low risk	None