The use of cannabis to control spasticity in multiple sclerosis is a hot topic. Bandolier has gathered together all the relevant references in a survey on the Bandolier Internet site. One of the more interesting is a wonderful description of the use of cannabis for treating a variety of conditions in India, by a Dr O'Shaughnessy in 1842. Another acutely observed description comes from a Dr Reynolds, FRS and Physician to Queen Victoria.
But added together, there really is little evidence for efficacy. Small randomised trials show no objective benefit, and most are case reports of one or a few patients. All are self-selected, though occasionally test-retest was usually positive. There is a large trial on cannabis and tetrahydrocannabinol currently ongoing in the UK. In the meantime, a small randomised trial holds out little hope .
This was a randomised crossover trial of placebo, THC and plan extract given orally in sixteen patients with progressive MS and spasticity. Four weeks of treatment with placebo, 2.5-5 mg THC, or plant extract with equivalent THC (identical appearance) was followed by four weeks of washout before the next treatment. A lower dose was used for two weeks, and doubled, if well tolerated, for the second two weeks of treatment.
Muscle tone was measured on a categorical scale (0=normal, 1=slight increase, 2=more marked increase, 3=considerable increase, 4=limb rigidity in flexion or extension) for arms and legs. Patients had to have a score of at least 2 for inclusion. EDSS and several other tests of function and ambulation were used.
Six of the 16 patients had primary and 10 secondary progressive MS. The average age was 46 years, with MS for an average of 15 years, and the mean EDSS score was 6.2. All completed all scheduled visits for all three treatments.
Active treatments conferred no benefit. Plant extract, but not THC, had significantly more adverse events. Five patients on plant extract reported subjective increased spasticity and one had an episode of acute psychosis.
Not much hope of benefit from this trial, and some suggestion of harm. The trial was good, but small, and we still have to wait for the big UK study. Bandolier will continue to add emerging evidence to its Internet site as it appears, and would be grateful if readers could tell us about evidence we may have missed.
© Bandolier: 10-Jun-2002