Limón Cano 1994.

Methods	Design: Randomised, double‐blind, parallel‐group trial Year: Not reported Country: Mexico
Participants	Patients: 17 patients (11 males/6 females) were randomised to one of the following two groups: SL buprenorphine: N = 10; mean age (SD?) = 53.2 (17.8) years. SD buprenorphine: N = 7; mean age (SD?) = 49.1 (17.1) years. Inclusion criteria: 17 patients with moderate to severe cancer pain that had not responded to treatment with non‐opioid and adjuvant analgesics according to the WHO analgesic ladder. Exclusion criteria: Patients with liver damage, renal or severe cardiorespiratory problems.
Interventions	SL buprenorphine arm: Drug: Buprenorphine. Dose/dosing: 0.2 to 0.4 mg buprenorphine in 1 to 2 tablets + 0.5 to 1 mL placebo SD injection from SD catheter in the anterior thorax. Formulation: SL. Route of administration: SL. Length of treatment: 24 hours it seems. "Subsequent doses were administered according to the requirements of the patients within a time interval of 4‐8 hours". Titration schedule: No titration. Rescue medication: No information provided. Other medication: No information provided. SD buprenorphine arm: Drug: Buprenorphine. Dose/dosing: 0.15 to 0.3 mg buprenorphine in 0.5 to 1 mL SD injection from SD catheter in the anterior thorax and 1 to 2 SL placebo tablets. Formulation: SD. Route of administration: SD. Length of treatment: 24 hours, it seems. "Subsequent doses were administered according to the requirements of the patients within a time interval of 4‐8 hours". Titration schedule: No titration. Rescue medication: No information provided. Other medication: No information provided.
Outcomes	"The analgesic response (decrease in pain intensity according to visual analogue scale), latency and duration of analgesia, side effects and difficulties to appreciate the procedure [patient preference?]."
Notes	Study free of commercial funding? No information reported. Groups comparable at baseline? The groups were comparable in terms of weight and height and baseline pain intensity. Unclear if they were balanced for gender and age. ITT analyses undertaken? No information specifically reported, but the analyses appear to be conducted as ITT. Study published in Spanish and lay‐translated by MSH.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The allocation to each treatment group: SL and SD was randomised and the study was double blind. No further information reported.
Allocation concealment (selection bias)	Unclear risk	See cell above.
Blinding of participants and personnel (performance bias) Pain	Unclear risk	Patients and doctors blinded. Blinding "kept closed until the end of the study". Unclear how blinding was achieved.
Blinding of participants and personnel (performance bias) Adverse events	Unclear risk	See cell above.
Blinding of outcome assessment (detection bias) Pain	Unclear risk	See cell above.
Blinding of outcome assessment (detection bias) Adverse events	Unclear risk	See cell above.
Incomplete outcome data (attrition bias) Pain	Low risk	Data appear to be available for all included patients.
Incomplete outcome data (attrition bias) Adverse events	Low risk	See cell above
Selective reporting (reporting bias)	Unclear risk	The outcomes are not well‐reported.
Other bias	Unclear risk	It is unclear whether the study is at high risk of other biases.
Were the patients adequately titrated?	High risk	The patients were not titrated.
For cross‐over trials: Are data available for both time periods?	Unclear risk	Not applicable.