Painful muscle stiffness, which affects the vast majority of people with multiple sclerosis, is eased with progressively stronger doses of cannabis extract (tetrahydrocannabinol), according to Phase III trial results published in the Journal of Neurology Neurosurgery and Psychiatry.

Painful muscle stiffness can seriously affect an MS (multiple sclerosis) patients’ ability to go about their daily routine activities; sleep quality may be affected and their mobility is reduced. Experts say that approximately 90% of MS patients experience painful muscle stiffness, with the pain causing considerable distress.

Unfortunately, treatments available today, some of which may be limited by toxicity, do not satisfactorily resolve the muscle stiffness symptoms. Consequently, a growing number of MS patients have tried out alternative remedies and therapies, including cannabis.

The investigators wrote, “it has been estimated that between 1% and 4% of the total UK MS population is using cannabis for symptom relief.”

Several studies have been conducted using tetrahydrocannabinol. In June 2012, A study aimed at determining whether the cannabis extract might slow down the course of progressive MS showed that there was no evidence to suggest this.

The Canadian Medical Association Journal (CMAJ) published a study in May 2012 which showed that smoking marijuana helps alleviate pain and muscle tightness in patients with MS.

The MUSEC (MUltiple Sclerosis and Extract of Cannabis) trial – in this double blind, placebo controlled, phase III study, 279 adult MS patients from 22 different specialist centers across the United Kingdom were randomly selected into one of two groups:

  • The cannabis extract group – 144 patients received tetrahydrocannabinol, a cannabis extract once a day for 12 weeks

  • The placebo group – 135 patients received a dummy pill, once a day for 12 weeks

All the participants had had stable disease for the previous six months. They were aged from 18 to 64 years and had had an MS diagnosis according to the McDonald criteria 11. Before enrolment, all of them had had troublesome and ongoing muscle stiffness for at least 3 months.

They started with a 2.5 mg dosage, which gradually increased to 25 mg during the first two weeks; for the remaining 10 weeks they remained on 25 mg daily.

The trial’s primary objective was to determine whether tetrahydrocannabinol might improve or alleviate muscle stiffness, the pain associated with it, as well as muscle spasms and sleep quality. The researchers used a validated 11-point rating scale.

87% of participants in the placebo group reached the top daily dose of 25 mg compared to 47% in the cannabis extract group.

The researchers reported that tetrahydrocannabinol had double the rate of muscle stiffness relief compared to the placebo at the end of the 12-week period.

15.7% of those on placebo experienced relief from muscle stiffness, compared to 29.4% on the cannabis extract.

There was a clear difference between the effectiveness of the cannabis extract over placebo after 4 and 8 weeks. Tetrahydrocannabinol was clearly superior to the placebo in relieving pain, improving sleep quality, and reducing the symptoms of muscle spasms at all points during the trial, the researchers added.

Among the patients who were not already on antispasmodic treatment, 40% gained relief from the cannabis extract compared to just over 16% in the placebo group.

More side effects were reported among the patients taking the cannabis extract, especially during the first two weeks of treatment. The most commonly reported side effects included gut problems and nervous system disorders – however, none of them was severe.

The authors concluded:

“The study met its primary objective to demonstrate the superiority of CE (cannabis extract) over placebo in the treatment of muscle stiffness in MS. This was supported by results for secondary efficacy variables. Adverse events in participants treated with CE were consistent with the known side effects of cannabinoids. No new safety concerns were observed”

The study was funded by Weleda AG, Arlesheim, Switzerland, and the Society for Clinical Research, Berlin, Germany.

Written by Christian Nordqvist