Delta-9-tetrahydrocannabinol (THC), the active constituent of marijuana, is an effective agent in the prevention of chemotherapy-induced nausea and vomiting.
To determine the effect of THC on gastric emptying of a radiolabelled solid food in humans.
Thirteen healthy volunteers underwent gastric emptying studies after receiving THC and placebo in a randomized double-blind fashion on 2 separate days. THC, at a dose of 10 mg/m2 of body surface area, or placebo were administered.
Gastric emptying after THC was slower than placebo in all subjects. Mean percentage of isotope remaining in the stomach was significantly greater than after placebo from 30 min (85.5 ± 4.3% vs. 94.2 ± 1.4% placebo and THC, respectively, P < 0.05) to 120 min (45.6 ± 7.2% vs. 73.9 ± 7.1% placebo and THC, respectively, P < 0.001) after the test meal. No correlation was found between plasma THC levels and the delay in gastric emptying.
THC at a dose used for preventing chemotherapy-induced nausea and vomiting significantly delays gastric emptying of solid food in humans. Therefore, the anti-emetic property of THC may be mediated through the central nervous system.