Feasibility, Safety and Preliminary Efficacy of 1:1 THC:CBD Cannabis Oil for Fibromyalgia Symptoms: Results From a Randomised, Double-Blind, Placebo-Controlled Pilot Trial.

Fibromyalgia is a chronic disorder characterised by widespread pain and other symptoms that substantially impact the quality of life. This double-blind, randomised, placebo-controlled trial primarily assessed feasibility (procedures and intervention adherence) and safety/tolerability of a 1:1 delta-9-tetrahydrocannabinol:cannabidiol (THC:CBD) cannabis oil (10 mg/mL each) in 24 adults with fibromyalgia, with secondary, preliminary assessment of efficacy across symptom domains. Participants completed a 4-week dose titration followed by 12 weeks of stable dosing. Of 77 prescreened individuals, 24 were randomised, yielding a screening-to-enrolment ratio of approximately 3:1 (31.2%). Recruitment reached 66.7% of the target (24/36); the shortfall was mainly due to geographic and legal barriers. Retention was 91.7% (22/24) and adherence was high, with all participants taking >/= 90% of the prescribed doses. The study medication was well tolerated in this small sample, with adverse events mostly mild and no serious events observed. Secondary outcomes suggested medium to large between-group effects favouring cannabis for pain reduction, improved sleep quality, and reduced fibromyalgia impact (FIQR), but findings should be interpreted cautiously given the small sample. Clinically meaningful FIQR improvement (predefined MCID 45.5%) occurred in 40% of the cannabis-treated participants versus 10% with placebo. For pain, 70% of the cannabis group reported >/= 30% reduction post-titration and at Week 12 (Placebo 20% and 40%, respectively). Fatigue and anxiety/depression showed no significant changes. A randomised trial of 1:1 THC:CBD oil appears feasible with excellent retention and adherence, though recruitment barriers need addressing. Preliminary safety and efficacy signals warrant confirmation in larger, adequately powered trials. Trial Registration: Australian New Zealand Clinical Trials Registry: ACTRN12623000345684.