Nabilone as an Adjunctive to Gabapentin for Multiple Sclerosis-Induced Neuropathic Pain: A Randomized Controlled Trial.
Turcotte D, Doupe M, Torabi M, Gomori A, Ethans K, Esfahani F, Galloway K, Namaka M. Pain Med. 2014 Oct . doi: 10.1111/pme.12569. [Epub ahead of print]
BACKGROUND:Neuropathic pain (NPP) is a chronic syndrome suffered by patients with multiple sclerosis (MS), for which there is no cure. Underlying cellular mechanisms involved in its pathogenesis are multifaceted, presenting significant challenges in its management.
METHODS: A randomized, double-blind, placebo-controlled study involving 15 relapsing-remitting MS patients with MS-induced NPP was conducted to evaluate nabilone combined with gabapentin (GBP). Eligible patients stabilized on GBP (≥1,800 mg/day) with inadequate pain relief were recruited. Nabilone or placebo was titrated over 4 weeks (0.5 mg/week increase) followed by 5-week maintenance of 1 mg oral nabilone (placebo) twice daily. Primary outcomes included two daily patient-reported measures using a 100-mm visual analog scale (VAS), pain intensity (VASpain ), and impact of pain on daily activities (VASimpact ). Hierarchical regression modeling was conducted on each outcome to determine if within-person pain trajectory differed across study groups, during 63-day follow-up.
RESULTS: After adjustment for key patient-level covariates (e.g., age, sex, Expanded Disability Status Scale, duration of MS, baseline pain), a significant group × time2 interaction term was reported for both the VASpain (P < 0.01) and VASimpact score (P < 0.01), demonstrating the adjusted rate of decrease for both outcomes was statistically greater in nabilone vs placebo study group. No significant difference in attrition rates was noted between treatments. Nabilone was well tolerated, with dizziness/drowsiness most frequently reported.
CONCLUSION: Nabilone as an adjunctive to GBP is an effective, well-tolerated combination for MS-induced NPP. The results of this study identify a novel therapeutic combination for use in this population of patients predisposed to tolerability issues that may otherwise prevent effective pain management.
Nabilone (Cesamet) is a synthetic cannabinoid receptor agonist and the side effect of dizziness drowsiness is consistent with cannabis use. Gabapentin was initially synthesized to mimic the gamma-aminobutyric acid (GABA), which is an inhibitory neurotransmitter. Some of its activity may involve interaction with voltage-gated calcium channels. Another possible mechanism of action is that gabapentin halts the formation of new synapses. This is an epilepsy drug that is used to treat pain. In MS cannabis is licenced to treat pain in Canada, so this study mixes the two drugs and the data suggest if you add nabilone on top of gabapentin, it may be better. However, with this trial there was only a group of fifteen and this too small to make any real conclusions. So it will need to be done again with a much bigger group size. Who is going to pay for this? Unless someone can find a way to repackage this to get a patent then pharma won't be interested. Lets hope that the authors of this study actually do this and show that this is of benefit, otherwise what was the point of doing the study in the first place.
Labels: Cannabinoid, gabapentin, Pain