Benefits of an add-on treatment with the synthetic cannabinomimetic nabilone on patients with chronic pain--a randomized controlled trial

<h4>Objective</h4>The aim of this study was to investigate the efficacy and efficiency of an add-on treatment with the synthetic cannabinomimetic nabilone on patients with chronic pain. Of major interest were the evaluation of the influence the treatment had on pain and on quality of life as well as the subjective assessment of positive effects and side effects by the study participants.<h4>Methods</h4>The placebo-controlled double-blinded pilot study was divided into a 14 week cross-over period (two 4 week medication phases plus wash-out phases) followed by a 16 week medication switch period with free choice of the study drugs (drug A and drug B) by the study participants. The principal inclusion criterion was chronic therapy-resistant pain in causal relationship with a pathologic status of the skeletal and locomotor system. The study participants chose the dosage of the study drug themselves (between 1 und 4 capsules/day, in the case of nabilone this corresponds to (1/4)-1 mg/day). Pain intensity was assessed by a visual analogue scale (VAS), quality of life by the Mezzich and Cohen QOL-score.<h4>Results</h4>Altogether, 30 patients were included and analyzed. From the results, it is obvious that throughout the cross-over periods the nabilone treatment was superior (medians [25%-; 75%-percentiles]: nabilone/placebo): decrease of the average spinal pain intensity within the last 4 weeks (DeltaVAS) 0.9 [0.0; 2.0] / 0.5 [0.0; 1.7], decrease of the current spinal pain intensity (DeltaVAS) 0.6 [0.0; 2.5] / 0.0 [-1.0, 1.0] (p = .006), decrease of the average headache intensity within the last 4 weeks (DeltaVAS) 1.0 [-1.0; 2.4] / 0.2 [-0.9; 1.0], increase of the number of days without headache within the last 4 weeks 2.0 [0.0; 6.5] / 0.0 [-5.0; 4.0], increase of the quality of life (DeltaQOL-Score) 5.0 [0.8; 10.8] / 2.0 [-2.3; 8.0]. In the medication switch period, the number of study participants who favoured nabilone (nabilone intake > or =85% of all medication days) was more than 4 times higher than those who favoured placebo. The number of days with nabilone intake was clearly higher than the number with placebo intake (medians: 89% vs. 11% of all medication days, p = .003).<h4>Conclusion</h4>In summary, the study results allow the conclusion that a majority of patients with chronic pain classify nabilone intake in addition to the standard treatment as a measure with a positive individual benefit-riskratio. Thus, this kind of treatment may be an interesting and attractive enrichment of analgetic therapy concepts.