A Phase Ib, Double Blind, Randomized Study of Cannabis Oil for Pain in Parkinson's Disease

BackgroundPain is common in Parkinson's disease (PD), but effective therapies are limited. ObjectivesTo determine the maximum tolerated dose (MTD) and safety of formulations of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) for pain in PD. MethodsIn this phase 1b, double-blind, randomized, single-center study, participants were randomized to three formulations of THC/CBD (18:0, 10:10, and 1:20). The MTD, adverse events (AE), and tolerability are described for each formulation. ResultsEight participants were randomized. The MTD was similar among groups (0.8-0.9 mL/daily), and there were no serious AE or study drop-outs. The most common AE were drowsiness and dizziness (three participants). Epworth sleepiness scale scores were higher in the high CBD formulation (1:20). ConclusionsIn patients with pain and PD, mixed formulations of THC/CBD were tolerated with no serious AE. Considering the safety profile, future phase II studies should be considered.