Are cannabinoids a new treatment option for pain in patients with fibromyalgia?
Preliminary studies suggest that the synthetic cannabinoid nabilone might be an effective therapy in patients with fibromyalgia. Skrabek et al. performed a double-blind, randomized, placebo-controlled clinical trial to analyze the effects of nabilone on pain and quality of life in patients with fibromyalgia. After 4 weeks of treatment (0.5 mg once daily in week 1, 0.5 mg twice daily in week 2, 0.5 mg in the morning and 1 mg in the evening in week 3, and 1 mg twice daily in week 4), patients who received nabilone (n = 15) experienced significant improvements in clinical pain, measured on a visual analog scale (P <0.02), Fibromyalgia Impact Questionnaire score (P <0.02) and the 10-point anxiety scale of the Fibromyalgia Impact Questionnaire (P <0.02). After a 4-week wash-out period at the end of the trial, all benefits were lost in the nabilone cohort, which returned to their baseline levels of pain and quality of life. Patients who received placebo (n = 18) experienced no change throughout the study. Although nabilone was not associated with serious adverse effects, some patients did experience drowsiness, dry mouth, vertigo and ataxia as a result of treatment.
- [Show abstract] [Hide abstract] ABSTRACT: Fibromyalgia syndrome (FMS) is a chronic pain syndrome characterized by diffuse musculoskeletal pain. In quantitative sensory testing studies, FMS patients display alterations in heat, cold, and mechanical sensitivity. Genetic studies support a key role for the biogenic amine system, and single nucleotide polymorphisms have been identified in serotonin and dopamine transporter and receptor genes of FMS patients. The pathophysiology of fibromyalgia includes contributions from both the ascending and descending somatosensory systems, and decreased central nervous system inhibition of peripheral nociceptive signalling. Three drugs have been approved for the treatment of FMS: Lyrica® (pregablin), Cymbalta® (duloxetine), and Savella® (milnacipran). These drugs were originally developed for indications other than FMS, and were later approved for FMS after successful clinical trials. One hurdle in the development of drugs specifically for FMS is the availability of preclinical animal models of the disease. Recently, several rodent models have been described with potential for translation to the human pain syndrome. In this review, we discuss recent developments toward understanding the pathophysiology of FMS, currently available pharmacologic therapy, ongoing clinical trials, and potential animal models of FMS.0Comments 8Citations
- [Show abstract] [Hide abstract] ABSTRACT: Chronic widespread pain (CWP) is a complex condition characterized by central hyperexcitability and altered descending control of nociception. However, nociceptive input from deep tissues is suggested to be an important drive. N-Acylethanolamines (NAEs) are endogenous lipid mediators involved in regulation of inflammation and pain. Previously we have reported elevated levels of the two NAEs, the peroxisome proliferator-activated receptor type-α ligand N-palmitoylethanolamine (PEA) and N-stearoylethanolamine (SEA) in chronic neck-/shoulder pain (CNSP). In the present study, the levels of PEA and SEA in women with CWP (n=18), CNSP (n=34) and healthy controls (CON; n=24) were investigated. All subjects went through clinical examination, pressure pain threshold measurements and induction of experimental pain in the tibialis anterior muscle. Microdialysis dialysate of the trapezius was collected before and after subjects performed a repetetive low-force exercise and analysed by mass spectrometry. The levels of PEA and SEA in CNSP were significantly higher at post-exercise compared to CWP and at both pre- and post-exercise compared to CON. Levels of both NAEs decreased significantly pre- to post- exercise in CWP. Intercorrelations existed between aspects of pain intensity and sensitivity and the level of the two NAEs in CWP and CNSP. This is the first study demonstrating that CNSP and CWP differ in levels of NAEs in response to a low-force exercise which induces pain. Increases in pain intensity as a consequence of low-force exercise was associated with low levels PEA and SEA in CNSP and CWP. These results indicate that PEA and SEA have antinociceptive roles in humans.0Comments 21Citations
- [Show abstract] [Hide abstract] ABSTRACT: Fibromyalgia is a syndrome characterized by the presence of chronic widespread pain, representing sensitization of the central nervous system. The pthophysiology of fibromyalgia is a complex and remains in evolution, encompassing diverse issues such as disturbed patterns of sleep, alter processing and decreased conditioned pain modulation at the spinal level, as well as increased connectivity between various pain - processing areas of the brain. This evolution is continuously uncovering potential novel therapeutic targets. Treatment of fibromyalgia is a multi - faceted endeavor, inevitably combining pharmacological as well as non - pharmacological approaches. 2δ ligands and selective nor-epinephrine - serotonin reuptake inhibitors are the current mainstays of pharmacological treatment. Novel re-uptake inhibitors targeting both nor -epinephrine and dopamine are potential additions to this armamentarium as are substance P antagonists, Opiod antagonism is another intriguing possibility. Canabinoid agonists hold promise in the treatment of fibromyalgia although current evidence is incomplete. Sodium Oxybate is a unique sleep - promoting medication while drugs those promot arousals such as modafilnil are also under investigation. In the current review, current and emerging therapeutic options for the syndrome of fibromyalgia are covered.0Comments 10Citations