Kleinman 1983.

Study characteristics
Methods	Randomised, double‐blind, 4‐period cross‐over study
Participants	16 people (9 men/7 women) aged 18‐53 years (median = 38 years) Tumour types: not reported Chemotherapy regimens: "Cancer chemotherapy known to cause acute gastrointestinal toxicity" Chemotherapy emetogenicity: unable to classify
Interventions	Prochlorperazine 10 mg + dronabinol 15 mg x 2 courses orally, n = 16 Prochlorperazine + placebo orally, n = 16
Outcomes	Episodes of nausea and vomiting 24 hours after chemotherapy, euphoria, sedation
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported
Allocation concealment (selection bias)	Unclear risk	Not reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	28/32 (87.5%) participants received prochlorperazine + THC, 24/32 (75%) participants received prochlorperazine + placebo (overall 52/64 (81%) participants received either of the 2 courses)
Selective reporting (reporting bias)	Low risk	Data reported for primary outcome
Other bias	Unclear risk	Assumed washout period sufficient. Unclear if paired analysis was performed. Unclear if groups were balanced at baseline
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Reported as "double‐blind" and "identical capsules used"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinding assumed as study reported as "double‐blind and identical capsules used"