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An experimental randomized study on the analgesic effects of pharmaceutical-grade cannabis in chronic pain patients with fibromyalgia

van de Donk, Tinea; Niesters, Mariekea; Kowal, Mikael A.b; Olofsen, Erika; Dahan, Alberta,*; van Velzen, Moniquea

doi: 10.1097/j.pain.0000000000001464
Research Paper: PDF Only

In this experimental randomized placebo-controlled 4-way crossover trial, we explored the analgesic effects of inhaled pharmaceutical-grade cannabis in 20 chronic pain patients with fibromyalgia. We tested 4 different cannabis varieties with exact knowledge on their [INCREMENT]9-tetrahydrocannabinol (THC) and cannabidiol (CBD) content: Bedrocan (22.4-mg THC, <1-mg CBD; Bedrocan International BV, Veendam, the Netherlands), Bediol (13.4-mg THC, 17.8-mg CBD; Bedrocan International BV, Veendam, the Netherlands), Bedrolite (18.4-mg CBD, <1-mg THC; Bedrocan International BV, Veendam, the Netherlands), and a placebo variety without any THC or CBD. After a single vapor inhalation, THC and CBD plasma concentrations, pressure and electrical pain thresholds, spontaneous pain scores, and drug high were measured for 3 hours. None of the treatments had an effect greater than placebo on spontaneous or electrical pain responses, although more subjects receiving Bediol displayed a 30% decrease in pain scores compared to placebo (90% vs 55% of patients, P = 0.01), with spontaneous pain scores correlating with the magnitude of drug high (ρ = −0.5, P < 0.001). Cannabis varieties containing THC caused a significant increase in pressure pain threshold relative to placebo (P < 0.01). Cannabidiol inhalation increased THC plasma concentrations but diminished THC-induced analgesic effects, indicative of synergistic pharmacokinetic but antagonistic pharmacodynamic interactions of THC and CBD. This experimental trial shows the complex behavior of inhaled cannabinoids in chronic pain patients with just small analgesic responses after a single inhalation. Further studies are needed to determine long-term treatment effects on spontaneous pain scores, THCCBD interactions, and the role of psychotropic symptoms on pain relief.

This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.

This experimental highly controlled trial in 20 patients with fibromyalgia shows that the cannabinoid THC, but not CBD, is effective in the treatment of fibromyalgia pain.

aDepartment of Anesthesiology, Leiden University Medical Center, Leiden, the Netherlands

bBedrocan International BV, Veendam, the Netherlands

Corresponding author. Address: Anesthesia and Pain Research Unit, Department of Anesthesiology, Leiden University Medical Center, H5-022, 2300 RC Leiden, the Netherlands. Tel: +31 71 526 9111. E-mail address: a.dahan@lumc.nl (A. Dahan).

Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.

Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (www.painjournalonline.com).

Received August 15, 2018

Received in revised form November 29, 2018

Accepted December 06, 2018

© 2019 International Association for the Study of Pain