Published in the May/June 2022 issue of the journal Pain Reports, this study examined the effectiveness of small doses of inhaled cannabis flower in reducing chronic pain over a period of about 9 months.
This study was funded by the maker of the metered dose inhaler used in the study, Syqe Medical LTD. All researchers were either directly or indirectly employed by the company. Nonetheless, it is one of the first studies to use very small, inhaled (via vapor) daily doses of THC (average = 1.5mg) to address chronic pain. This is important because the doses were largely small enough so the patients felt none of the euphoric, or psychotropic effects of THC.
The 143 participants were on average 62 years of age and 54% were men. Chronic neuropathic pain was the main type of pain treated (72%), but others included chronic musculoskeletal pain (10%), and cancer pain (6%).
The metered dose inhaler would deliver either 0.25mg or 0.50mg of THC and any secondary cannabinoids and terpenes per 2-4 second inhalation, several times a day. The average duration of effects was about 150 minutes. The device prevented inhalation of more than the set amounts. The inhaler used heat below combustion to vaporize whole flower from preset multi-packs designed specifically for use with the Syqe inhaler.
Almost half (46%) of the patients experienced a pain intensity reduction of more than 30%. Over three-quarters (76%) reported a reduction in pain intensity of at least 1 NPS point on a 10 point scale. 17% reported no change, and 7% reported an increase in pain intensity of at least 1 point.
This reinforces the common wisdom that cannabinoid medicine does not work for everyone, and we don't always know why. The authors found "no unique demographic or pain etiology characterization that could distinguish them from patients who responded to the treatment".
In an encouraging observation, they said 58% of patients reported they were able to reduce their opioid doses at 120 days after starting treatment with the inhaler.
"Medical cannabis treatment with the Syqe Inhaler demonstrated overall long-term pain reduction, quality of life improvement, and opioid-sparing effect in a cohort of patients with chronic pain, using just a fraction of the amount of MC compared with other modes of delivery by inhalation."
The full text paper is here at the International Association for the Study of Pain's publishing site.