THC and gabapentin interactions in a mouse neuropathic pain model.
Clinical studies have shown that the major psychoactive ingredient of Cannabis sativa Δ9-tetrahydrocannabinol (THC) has some analgesic efficacy in neuropathic pain states. However, THC has a significant side effect profile. We examined whether the profile of THC could be improved by co-administering it with the first-line neuropathic pain medication gabapentin. This was done using the chronic constriction injury (CCI) model of neuropathic pain in C57BL6 mice. At 8 days post-CCI nerve injury, acute systemic administration of gabapentin produced a dose-dependent decrease in CCI-induced mechanical and cold allodynia, and increased motor incoordination. Coadministration of THC and gabapentin in a fixed-ratio dose-dependently reduced mechanical and cold allodynia, and produced all the side-effects observed for THC, including motor incoordination, catalepsy and sedation. Isobolographic analysis indicated that the ED