Staquet 1978b.

Study characteristics
Methods	Purpose of the study: reducing moderate‐to‐severe cancer pain Study setting: 1 university hospital in Belgium Study period: not reported Study design: double‐blind, randomised, placebo‐controlled, cross‐over design Study duration: 1 day each. Regular medication was stopped 3 hours before the intake of the medication
Participants	Type of cancer: no details reported Inclusion criteria: continuous moderate‐to‐severe pain for ≥ 3 days at time of admission to study Exclusion criteria: receiving large doses of narcotics, insufficient mental clarity to judge discomfort or relief, serious gastrointestinal pathology, renal and hepatic diseases susceptible to interfere with drug metabolism or excretion Synthetic THC: 15 participants; gender not reported; aged 21–75 years; race not reported; type of cancer pain: not reported; pain medication: not reported; previous cannabis use: not reported
Interventions	Synthetic nitrogen‐containing benzopyran derivative (modification of delta‐I‐trans‐THC): 4 mg single dose, fixed dosage PO Secobarbital: 50 mg single dose, fixed dosage (not used for comparison, because secobarbital is not used for cancer pain treatment) Placebo Rescue medication: none Allowed cotherapies: no details reported
Outcomes	Proportion of participants reporting no worse than mild pain on treatment at 14 days after start of treatment (typically < 30/100 mm on a 100‐mm VAS or < 3 on an 11‐point NRS): not assessed Patient impression to be much or very much improved: not assessed Withdrawal due to adverse events: no details of assessment reported Combined responder: not assessed Pain relief ≥ 30%: not reported; imputation method not applicable because baseline pain scores not reported Pain relief ≥ 50%: not reported; imputation method not applicable because baseline pain scores not reported Mean pain intensity: hourly ratings of the severity of pain (0, absent; 1, mild; 2, moderate; 3, severe) were used to arrive at hourly pain reduction scores. The sum of hourly pain reduction or relief scores for a given 6‐hour observation period (total reduction or relief scores) was used as a basis for statistical analysis Sleep problems: not assessed Depression: not assessed Anxiety: not assessed Daily maintenance opioid therapy dose: not assessed Daily breakthrough opioid therapy dose: not assessed Withdrawals due to lack of efficacy: not reported Nervous system disorders adverse effects: reports on drowsiness without information how the symptoms were assessed Psychiatric disorders adverse effects: not assessed Serious adverse events: not reported
Notes	Funding: not reported Conflicts of interest: not declared
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details reported.
Allocation concealment (selection bias)	Unclear risk	No details reported.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Identical capsules."
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No details reported.
Incomplete outcome data (attrition bias) All outcomes	High risk	Completer analysis.
Selective reporting (reporting bias)	Unclear risk	No prepublished study protocol available.
Selection bias	Low risk	Identical baseline data of the study groups due to cross‐over design.