Ungerleider 1982.

Study characteristics
Methods	Randomised, double‐blind, 2‐period cross‐over study
Participants	214 people (107 men/107 women) aged 18‐82 years (median = 47 years) Tumour types: "wide variety of neoplasms" Chemotherapy regimens: antibiotics (70 people), nitrosoureas (21 people), alkylating agents (119 people), antimetabolites (82 people), vinca‐alkaloids (60 people), hormones (13 people), miscellaneous (33 people) and combinations. Rated as high for 66% of people, moderate for 27% of people or low for 7% of people emetic potential Chemotherapy emetogenicity: unable to classify ‐ unknown combinations
Interventions	Dronabinol 7.5 mg for < 1.4/m2, 10 mg for 1.4‐1.8 m2 or 12.5 mg for > 1.8 m2 orally, n = 214 Prochlorperazine 10 mg 1 hour prior to chemotherapy, then every 4 hours x 4 doses per day x all chemotherapy days orally, n = 214
Outcomes	Episodes of nausea and vomiting during 24 hours; withdrawal due to adverse effects; episodes of sedation, depression, feeling high
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Table of random numbers
Allocation concealment (selection bias)	Unclear risk	Not reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	172/214 (80%) participants received THC, 181/214 (85%) received prochlorperazine
Selective reporting (reporting bias)	Low risk	Data reported for primary outcome
Other bias	Low risk	Washout period 1‐3 weeks. Paired analysis was performed. Groups were balanced at baseline
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Reported as "double‐blind"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Blinding assumed as study reported as "double‐blind"