Table 2.
Study information.
| Article | Subjects | Study design / PEDro score | Treatment | Concomitant medications | Pain measure | Outcome | Effect size |
|---|---|---|---|---|---|---|---|
| Maurer et al.32 | 1 | RCT, double-blind crossover / 5 | 5 mg of oral delta-9-THC vs. active comparator (50 mg codeine p.o) vs. inactive placeb0. Conditions applied 18 times each in a randomized and balanced order over 5 months. | Continued all other concurrent medication as usual (baclofen & clonazepam) | VAS of 50 mm, poles = ‘none’ to ‘very strong’ at four time points: after taking, before falling asleep, at night, & when getting up. | P < 0.05 (THC vs inactive placebo) No differences between THC vs active comparator. | d = 1.13-1.89 (THC vs inactive placebo) d = 0.01-0.88 (THC vs active comparator) |
| Hagenbach et al.35 | 22 | Open label / 1 | 10 mg oral dronabinol. Titrate Up: 10–14 days starting day 2 based on individual preference. Duration: 6 weeks. Washout period: 7 days. Mean daily dose = 31 mg (range: 15–60 mg) | Stopped all spasmolytic medications prior to enrollment; required urine drug screen. | 0=no pain, 1=minimal, 2=minor, 3=moderate, 4=strong, 5=very strong, 6=intolerable. | P = 0.047 | Data unavailable. |
| Rintala et al.34 | 7 | RCT, double-blind, crossover / 6 | 5 mg of oral dronabinol or active placebo (25 mg of diphenhydramine). Titrate Up: 12 days. Stabilization: 7 days. Maintenance: 28 days. Titrate Down: 9 days. Washout period: 7 days. Maximum daily dose: 20 mg of dronabinol and 75 mg of diphenhydramine. | Stopped all pain medications prior to enrollment. Oxycodone-acetaminophen 5-325 mg for breakthrough pain. | BPI pain intensity item: NRS (0 ‘no pain’ to 10 ‘pain as bad as you can imagine’) | P = 0.102 (dronabinol vs active placebo) | Data unavailable. |
| GW Pharmaceuticals Ltd. 2012 | 116 | RCT, quadruple-blind, parallel-group / 10 | Nabiximols or inactive placebo via oromucosal spray. Each puff delivered 100 μl. Subjects self-titrated. Maximum permitted dose: eight puffs in any 3-hour period and 48 puffs in any 24-hour period. Duration: 21–30 days. | Stable medication regime for 4 weeks and stopped all cannabinoids for 7 days prior to enrollment. Acetaminophen for breakthrough pain. | Central Neuropathic Pain NRS (0 = ‘no pain’ and 10 = ‘worst possible pain’) | P = 0.708 (Nabiximols vs inactive placebo) | ±d = 0.039 |
| Wilsey et al.31 A | 42 | RCT, double-blind, crossover / 8 | Vaporized 2.9% or 6.7% delta-9-THC, or inactive placebo applied during 8-hour sessions. Washout period: 3 day minimum. Randomized order of conditions. Cumulative dosing scheme: 4 puffs after baseline; then 4–8 puffs after 240 min. For all conditions, the most frequent number of puffs = 8. | Continued all other concurrent medication as usual. Stopped all cannabis use for 7 days prior to enrollment. | NRS (0 = ‘no pain’ and 10 = ‘worst possible pain’) | P < 0 .05 (THC vs inactive placebo) | *d ≈ 0.7 (2.9% THC vs inactive placebo) *d ≈ 1.0 (6.7% THC vs inactive placebo) |
| Wilsey et al.31 B | 42 | RCT, double-blind, crossover / 8 | Vaporized 2.9% delta-9-THC, 6.7% delta-9-THC, or inactive placebo applied during 8-hour sessions. Washout period: 3 day minimum. Randomized order of conditions. Cumulative dosing scheme: 4 puffs after baseline; then 4–8 puffs after 240 min. The mean range of cannabis vaporized = 45.9 mg (29.9–83.8 mg) during the 2.9% THC sessions and 56.3 mg (15.7–172.9 mg) during the 6.7% THC sessions. | Continued all other concurrent medication as usual. Stopped all cannabis use for 7 days prior to enrollment. | 10-item NPS scale (0 = ‘no pain’ and 10 =‘strongest pain imaginable’) | Greater reduction in itching (P = 0.0174) and burning (P=0.0395) for 6.7% delta-9-THC | Data unavailable. |
PEDro = Physiotherapy Evidence Database scale (0-11). VAS = Visual Analog Scale. BPI: Brief Pain Inventory. NRS = Numerical Rating Scale. NPS = Neuropathic Pain Scale. Bolded items are statistically significant. ±Calculated effect size. *Estimated effect size.