THC and a Standard Antiemetic Were Equally Effective Against Chemotherapy Nausea in 214 Patients

Double-blind, crossover design with 214 subjects. THC was dosed by body surface area (7.5, 10, or 12.5 mg). Prochlorperazine was 10 mg fixed dose. Both given orally one hour before chemotherapy then every four hours for four doses. Assessed nausea, vomiting, appetite, mood, activity, concentration, and social interaction.

This was one of the largest and best-designed early trials of THC as an antiemetic. The finding of equivalence rather than superiority was clinically important: it meant THC was a legitimate alternative but not necessarily better than existing options. The "unblinding" effect, where patients who recognized THC responded better, raised important questions about expectation and placebo effects in cannabinoid research.

This trial contributed to the evidence base that led to dronabinol's FDA approval in 1985. Its finding that THC side effects were associated with better nausea control and were tolerated by patients helped shape the understanding that cannabinoid "side effects" and therapeutic effects may be linked.

Crossover design means each patient received both treatments, which may introduce carryover effects. The "unblinding" finding suggests the double-blind was not perfect, potentially biasing results. The study used oral THC with its variable absorption.