Authors: Schley, Marcus1; Legler, Andreas1; Skopp, Gisela2; Schmelz, Martin1; Konrad, Christoph1; Rukwied, Roman1 Source: Current Medical Research and Opinion, Volume 22, Number 7, July 2006 , pp. 1269-1276(8) Publisher: LibraPharmDelta-9-THC based monotherapy in fibromyalgia patients on experimentally induced pain, axon reflex flare, and pain relief
Abstract:
Objective: Fibromyalgia (FM) is a chronic pain syndrome characterized by a distinct mechanical hyperalgesia and chronic pain. Recently, cannabinoids have been demonstrated as providing anti-nociceptive and anti-hyperalgesic effects in animal and human studies. Here, we explored in nine FM patients the efficacy of orally administered delta-9-tetrahydrocannabinol (THC) on electrically induced pain, axon reflex flare, and psychometric variables.Research design and methods: Patients received a daily dose of 2.5-15 mg of delta-9-THC, with a weekly increase of 2.5 mg, as long as no side effects were reported. Psychometric variables were assessed each week by means of the West Haven-Yale Multidimensional Pain Inventory (MPI), Pittsburgh Sleep Quality Index (PSQI), Medical outcome survey-short form (MOS SF-36), the Pain Disability Index (PDI), and the Fibromyalgia Impact Questionnaire (FIQ). In addition, patients recorded daily, in a diary, their overall pain intensity on a numeric scale. Each week, pain and axon reflex flare was evoked experimentally by administration of high intensity constant current pulses (1 Hz, pulse width 0.2 ms, current increase stepwise from 2.5-12.5 mA every 3 minutes) delivered via small surface electrodes, attached to the volar forearm skin.
Main outcome measures: Daily pain recordings by the patient, experimentally induced pain, and axon reflex flare recorded by a laser Doppler scanner.
Results: Five of nine FM patients withdrew during the study due to adverse side effects. Delta-9-THC had no effect on the axon reflex flare, whereas electrically induced pain was significantly attenuated after doses of 10-15 mg delta-9-THC (p < 0.05). Daily-recorded pain of the FM patients was significantly reduced (p < 0.01).
Conclusions: This pilot study demonstrated that a generalized statement that delta-9-THC is an analgetic drug cannot be made. However, a sub-population of FM patients reported significant benefit from the delta-9-THC monotherapy. The unaffected electrically induced axon reflex flare, but decreased pain perception, suggests a central mode of action of the cannabinoid.
Keywords: AXON REFLEX FLARE; CANNABINOIDS; DELTA-9-THC; FIBROMYALGIA; PAIN
Document Type: Research article
DOI: 10.1185/030079906X112651
Affiliations: 1: Department of Anaesthesiology and Intensive Care Medicine, Faculty of Clinical Medicine Mannheim, University of Heidelberg, Mannheim, Germany 2: Institute of Forensic Toxicology, University of Heidelberg, Heidelberg, Germany
Nabilone for the Treatment of Pain in Fibromyalgia
The Journal of Pain
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doi:10.1016/j.jpain.2007.09.002 
Copyright © 2007 American Pain Society Published by Elsevier Inc.
Ryan Quinlan Skrabek
, a, 
, Lena Galimovaa and Karen Ethansand Daryl Perrya
aSection of Physical Medicine and Rehabilitation, University of Manitoba, Rehabilitation Hospital, Health Sciences Centre, Winnipeg, Manitoba, Canada
Received 19 April 2007; revised 27 August 2007; accepted 26 September 2007. Available online 5 November 2007.
Abstract
A randomized, double-blind, placebo-controlled trial was conducted to determine the benefit of nabilone in pain management and quality of life improvement in 40 patients with fibromyalgia. After a baseline assessment, subjects were titrated up on nabilone, from 0.5 mg PO at bedtime to 1 mg BID over 4 weeks or received a corresponding placebo. At the 2- and 4-week visits, the primary outcome measure, visual analog scale (VAS) for pain, and the secondary outcome measures, number of tender points, the average tender point pain threshold, and the Fibromyalgia Impact Questionnaire (FIQ), were evaluated. After a 4-week washout period, subjects returned for reassessment of the outcome measures. There were no significant differences in population demographics between groups at baseline. There were significant decreases in the VAS (−2.04, P< .02), FIQ (−12.07, P < .02), and anxiety (−1.67, P < .02) in the nabilone treated group at 4 weeks. There were no significant improvements in the placebo group. The treatment group experienced more side effects per person at 2 and 4 weeks (1.58, P < .02 and 1.54, P < .05), respectively. Nabilone appears to be a beneficial, well-tolerated treatment option for fibromyalgia patients, with significant benefits in pain relief and functional improvement.
Perspective
To our knowledge, this is the first randomized, controlled trial to assess the benefit of nabilone, a synthetic cannabinoid, on pain reduction and quality of life improvement in patients with fibromyalgia. As nabilone improved symptoms and was well-tolerated, it may be a useful adjunct for pain management in fibromyalgia.
Key words: Nabilone; cannabinoid; fibromyalgia; pain