Separate and combined effects of gabapentin and INCREMENT9-tetrahydrocannabinol in humans discriminating INCREMENT9-tetrahydrocannabinol.
The aim of the present study was to examine a potential mechanism of action of gabapentin to manage cannabis-use disorders by determining the interoceptive effects of gabapentin in cannabis users discriminating INCREMENT-tetrahydrocannabinol (INCREMENT-THC) using a pharmacologically selective drug-discrimination procedure. Eight cannabis users learned to discriminate 30 mg oral INCREMENT-THC from placebo and then received gabapentin (600 and 1200 mg), INCREMENT-THC (5, 15, and 30 mg), and placebo alone and in combination. Self-report, task performance, and physiological measures were also collected. INCREMENT-THC served as a discriminative stimulus, produced positive subjective effects, elevated heart rate, and impaired psychomotor performance. Both doses of gabapentin substituted for the INCREMENT-THC discriminative stimulus and engendered subjective and performance-impairing effects that overlapped with those of INCREMENT-THC when administered alone. When administered concurrently, gabapentin shifted the discriminative-stimulus effects of INCREMENT-THC leftwardupward, and combinations of INCREMENT-THC and gabapentin generally produced larger effects on cannabinoid-sensitive outcomes relative to INCREMENT-THC alone. These results suggest that one mechanism by which gabapentin might facilitate cannabis abstinence is by producing effects that overlap with those of cannabinoids.