High doses of CBD do not help reduce osteoarthritis pain when used with paracetamol

This was a randomized, double-blind, placebo-controlled clinical trial investigating the effectiveness of daily use of 600mg CBD to reduce osteoarthritis knee pain (KOA) when used in conjunction with paracetamol. It was published in The Lancet Regional Health - Europe in December 2023.

Paracetamol has been around for over 50 years and is widely prescribed for osteoarthritis pain, and this study showed that it did indeed reduce osteopathic knee pain scores.

They measured pain using the Western Ontario and McMasters Universities Osteoarthritis (WOMAC) Index, which was developed specifically for hip and knee osteoarthritis. The subscale pain levels used ranged from 0 to 10. Each study participant had baseline (starting) scores of 5 or more (6 was the average).

86 patients were included and evenly split between the CBD and placebo groups. The average age was 62.8 and about 67% were women. All patients took 3g of parecetamol per day in addition to placebo (n=43) or 600mg CBD (n=43) for 8 weeks. Patients in the CBD group took 3 capsules a day, each containing 200mg of 99.8% pure CBD. 

They found that both groups experienced a fairly significant reduction in pain scores (-2.5 for CBD and -2.4 placebo), but there was no significant difference between them. In other words, CBD did not help.

Authors' results and conclusion:

Mean reduction in WOMAC pain subscale was 2.5 (95% CI: 1.8–3.3) in the cannabidiol group and 2.4 (95% CI: 1.7–3.2) in the placebo group with no significant group difference (p = 0.80). 

In KOA patients, oral high-dose add-on cannabidiol had no additional analgesic effect compared to adding placebo to continued paracetamol. 

 

Our opinion:

600mg is a very high dose of CBD isolate. Even the authors stated, 600mg CBD isolate "was much higher than in any previous CBD trial for chronic pain". 

Cannabinoids have been shown to be bi-phasic and sometimes exhibit a bell-shaped dose-response curve.

Bi-phasic means that low and high doses can have the exact opposite effects.

A bell-shaped dose response curve means that there is a "sweet spot" dose that is most effective while smaller or larger doses are not as effective.

Here's our summary of a recent research article on this topic from March 2023. There are also 20 other references of biphasic effects summarized on our site.

We know of many "anecdotes" from osteoarthritis pain patients that CBD doses of 20 to 100 mg per day are effective for reducing their osteoarthritis pain.

In short, the dose amount is extremely important with CBD, and with cannabinoids in general. 

 

The full text article is here via PubMed Central.

Source:

Pramhas S, Thalhammer T, Terner S, Pickelsberger D, Gleiss A, Sator S, Kress HG. Oral cannabidiol (CBD) as add-on to paracetamol for painful chronic osteoarthritis of the knee: a randomized, double-blind, placebo-controlled clinical trial. Lancet Reg Health Eur. 2023 Nov 10;35:100777. doi: 10.1016/j.lanepe.2023.100777. PMID: 38033459; PMCID: PMC10682664