Cannabinoids are emerging as potential options for neuropathic pain treatment. This study evaluated an oral cannabinoid, nabilone, in the treatment of refractory human diabetic peripheral neuropathic pain (DPN). We performed a single-center, randomized, double-blind, placebo-controlled, flexible-dose study with an enriched enrollment randomized withdrawal design. DPN subjects with a pain score ≥ 4 (0-10 scale) continued regular pain medications and were administered single-blinded adjuvant nabilone for 4 weeks. Subjects achieving ≥ 30% pain relief (26/37) were then randomized and treated with either flexible-dose nabilone 1-4 mg/day (n=13) or placebo (n=13) in a further 5-week double-blind treatment period, with 30% (11/37) of subjects deemed run-in-phase nabilone nonresponders. For nabilone run-in-phase responders, there was an improvement in the change in mean end-point neuropathic pain vs placebo (mean treatment reduction of 1.27; 95% confidence interval 2.29-0.25, P=0.02), with an average nabilone dose at end point of 2.9 ± 1.1mg/day, and improvements from baseline for the anxiety subscale of the Hospital Anxiety and Depression Scale, the Medical Outcomes Study sleep scale problems index, and the European Quality of Life-5-Domains index score (each P<0.05). Nabilone run-in-phase responders reported greater global end-point improvement with nabilone than with placebo (100% vs 31%; P<0.05). Medication-related confusion led to discontinuation in 2/37 subjects during single-blind nabilone treatment. Potential unmasking occurred in 62% of both groups. Flexible-dose nabilone 1-4 mg/day was effective in relieving DPN symptoms, improving disturbed sleep, quality of life, and overall patient status. Nabilone was well tolerated and successful as adjuvant in patients with DPN.
Neuropathic pain (NeP) is prevalent in patients with peripheral neuropathy (PN), regardless of etiology. We sought to compare the efficacy of the cannabinoid nabilone as either monotherapy or adjuvant therapy with a first-line medication for NeP, gabapentin, in a patient population with PN-NeP. Patients diagnosed with PN-NeP were permitted to initiate monotherapy (nabilone or gabapentin) or add one of these two medications (adjuvant therapy) to their existing NeP treatment regimen in a non-randomized open-label nature. Baseline data collected included a primary outcome (visual analog scores [VAS] of pain) and secondary outcomes (quality of life [EuroQol 5 Domains and Short-Form 36] assessments and assessments of sleep [Medical Outcomes Sleep Study Scale {MOSSS}], anxiety and depression [Hospital Anxiety and Depression Scale], and pain [Brief Pain Inventory]). Reassessment and modulation of dosing and/or medications occurred at 3- and 6-month intervals. Medication adverse effects and drug efficacy, as well as questionnaires, were assessed at 6 months. Matched analysis of variance testing was performed to compare 3- and 6-month scores with baseline, as well as to compare therapies at equal time points. Significant improvements in pain VAS were seen in all treatment groups at 6 months. Numerous sleep parameters within MOSSS, Brief Pain Inventory, and Short-Form 36 improved in patients receiving nabilone or gabapentin either as monotherapy or adjuvant treatment. Hospital Anxiety and Depression Scale-A scores were significantly improved in all treatment groups. Sleep adequacy and the sleep problems index within the MOSSS improved in nabilone monotherapy patients in particular. The benefits of monotherapy or adjuvant therapy with nabilone appear comparable to gabapentin for management of NeP. We advocate for head-to-head randomized, double-blind studies for current therapies for NeP in order to determine potential advantages beneficial in this patient population. (PsycInfo Database Record (c) 2021 APA, all rights reserved)
