In a phase 1b trial of eight Parkinson's disease patients, three THC/CBD formulations were tolerated at similar doses with no serious adverse events, though drowsiness and dizziness were common.
Read this if you have Parkinson's disease with pain and are considering cannabis-based treatment options.
0 serious AEsNo serious adverse events in any of the three THC/CBD formulations tested
What the researchers found
Eight participants were randomized to one of three THC:CBD ratios (18:0, 10:10, or 1:20). The maximum tolerated dose was similar across all formulations (0.8-0.9 mL/day). There were no serious adverse events and no study dropouts. The most common side effects were drowsiness and dizziness (three participants). The high-CBD formulation (1:20) was associated with higher sleepiness scores on the Epworth scale.
Why it matters
Pain affects the majority of Parkinson's disease patients but has few effective treatments. This small safety trial establishes that cannabis oil formulations can be tolerated in PD patients, clearing the path for larger efficacy studies.
The numbers in context
- 8 participants randomized
- 3 formulations: THC:CBD 18:0, 10:10, and 1:20
- Maximum tolerated dose: 0.8-0.9 mL/daily across groups
- 0 serious adverse events
- 0 study dropouts
- Most common AE: drowsiness and dizziness (3 participants)
How the study worked
Phase 1b, double-blind, randomized, single-center study. Participants randomized to three THC/CBD formulations. Primary outcomes were maximum tolerated dose, adverse events, and tolerability.
Who was studied
8 Parkinson's disease patients with pain
What this study cannot tell us
Extremely small sample size (8 total participants). Not designed to test efficacy for pain relief. Single-center study. The MTD was similar across groups, making it difficult to assess formulation-specific differences.
How to read the evidence
Phase 1b randomized controlled trial. Well-designed for safety assessment but too small for efficacy conclusions.
When this study was published
Published in 2023. Part of growing clinical interest in cannabis for Parkinson's disease symptoms.
The bigger picture
Cannabis-based therapies for Parkinson's disease are generating growing interest for symptoms beyond motor function, including pain, sleep, and anxiety. Phase 1b trials like this are necessary stepping stones, but much larger studies are needed to determine whether cannabis oil actually relieves PD-related pain.
Questions still open
- Which THC:CBD ratio would be most effective for PD pain in a larger trial?
- Does the drowsiness from high-CBD formulations offset potential pain benefits in PD patients?
- Would longer treatment durations change the tolerability profile?
Read the original research
A Phase Ib, Double Blind, Randomized Study of Cannabis Oil for Pain in Parkinson's Disease.
Movement disorders clinical practice, 10(7), 1114-1119
Citation
Di Luca, Daniel G; Gilmour, Gabriela S; Fearon, Conor; Swinkin, Emily; Freitas, Eliza; Kuhlman, Greg; Fox, Susan H; Mestre, Tiago. (2023). A Phase Ib, Double Blind, Randomized Study of Cannabis Oil for Pain in Parkinson's Disease.. Movement disorders clinical practice, 10(7), 1114-1119. https://doi.org/10.1002/mdc3.13754