Table 4.
Studies, outcomes, and conclusions.
| Study | Study Design | Intervention | Outcomes | Conclusions |
|---|---|---|---|---|
| Skrabek et al. (2008) [19] | RCT, parallel | Nabilone vs. placebo | Compared to placebo, the nabilone group demonstrated decreases in the VAS (2.04, p < 0.02), FIQ (12.07, p < 0.02), and anxiety (1.67, p < 0.02) at 4 weeks. More side effects were noted in the nabilone group at 2 and 4 weeks, with no major improvements measured in the placebo group | Nabilone is a well-tolerated treatment option for patients with fibromyalgia, with demonstrated benefits in pain relief and functional improvements in quality of life and anxiety |
| Ware et al. (2010) [16] | RCT, crossover | Nabilone vs. amitriptyline | Though both amitriptyline and nabilone were effective in improving sleep, nabilone proved superior to amitriptyline (Insomnia Severity Index difference 3.2; 95% confidence interval 1.2–5.3). Nabilone was rated better for restfulness (Leeds Sleep Evaluation Questionnaire difference 0.5 [0.0–1.0]), but not for wakefulness (0.3 [0.2 to 0.8]). No effects on pain, mood, or QOL were observed. Side effects were mostly mild–moderate and were more frequent with nabilone, with the most common symptoms being dizziness, nausea, and dry mouth | Nabilone is well tolerated in patients that have fibromyalgia and can improve their sleep. Low-dose nabilone at bedtime may prove an effective alternative to amitriptyline for sleep management in this population |
| Fiz et al. (2011) [11] | OBS, cross-sectional | Survey of cannabis users vs. non-users | Two hours following cannabis consumption, measured outcomes indicated a statistically significant (p = 0.001) improvement in subjects’ reported pain and stiffness, relaxation, and increased somnolence and feeling of wellbeing. Additionally, the mental health component of the SF-36 was significantly higher (p = 0.05) in cannabis users than in non-users | Cannabis use was associated with improvements in some fibromyalgia symptoms, including pain, feelings of wellbeing and relaxation, and mental health scores |
| Van de Donk et al. (2019) [17] | RCT, crossover | Inhaled THC/CBD combo vs. placebo | None of the treatment modalities impacted spontaneous or electrical pain responses when compared to the placebo. Cannabis varieties that contained THC resulted in a significant increase in subjects’ pain threshold for pressure when compared to the placebo (p < 0.01). Though inhalation of cannabidiol was noted to increase THC plasma concentrations, the analgesic effects associated with THC were found to be diminished in this route of administration | Analgesic benefits were limited to cannabis varieties containing THC and were observed exclusively in the evoked pressure pain model. None of the different treatments in this study were better than the placebo in improving spontaneous pain scores |
| Yassin et al. (2019) [12] | OBS, crossover | Inhaled cannabis vs. oxycodone/naloxone/duloxetine | While standard analgesic therapy showed modest improvements in scores when compared to baseline, the addition of medical cannabis resulted in a significantly higher improvement in all patient-reported outcomes at 3 months. This observed improvement was maintained at 6 months. Range of motion improved after 3 months of cannabis therapy and showed continued improvement at 6 months | Adjunct treatment with medical cannabis therapy in combination with other analgesics can alleviate lower-back pain in patients suffering from fibromyalgia |
| Sagy et al. (2019) [14] | OBS | Cannabis (oil, smoke, or both) | Pain was reduced from a baseline median of 9.0 to 5.0 (p < 0.001); 81.1% of patients achieved a treatment response. Factors associated with treatment outcomes included age over 60 years (odds ratio (OR) 0.34, 95% C.I 0.16–0.72), spasticity (OR 2.26, 95% C.I 1.08–4.72), concerns about cannabis treatment (OR 0.36, 95% C.I 0.16–0.80), and previous cannabis use (OR 2.46 95% C.I 1.06–5.74). The most common adverse effects were mild, including dizziness, dry mouth, and GI symptoms | Cannabis was found to be a well-tolerated and effective treatment modality for fibromyalgia symptoms. |
| Chaves et al. (2020) [18] | RCT, parallel | THC-rich cannabis oil vs. olive oil | There were no significant differences in baseline FIQ score between the groups at the beginning of the study. After the intervention, the cannabis oil group experienced a significant decrease in FIQ score relative to the olive-oil placebo (p = 0.005), as well as when compared with their own baseline score (p < 0.001). The cannabis group reported significant improvements in the “feel good”, “pain”, “do work”, and “fatigue” scores. The placebo group reported significant improvements in the “depression” score following the intervention. No major adverse effects were observed | Phytocannabinoids can be a low-cost therapy option with minimal adverse effects to alleviate symptoms and increase the quality of life in patients experiencing fibromyalgia |
RCT, randomized controlled trial; OBS, observational study; CBD, cannabidiol; THC, tetrahydrocannabinol; VAS, visual analog scale; PSQI, Pittsburgh sleep quality index; FIQR, Fibromyalgia Impact Questionnaire; AEs, adverse events; QOL, quality of life; LBP, lower-back pain; ROM, range of motion.