anecdotal accounts from marijuana users with MS and spinal cord injuries, suggest that carefully designed clinical trials testing the effects of cannabinoids on muscle spasticity would be worthwhile.

Two factors complicate the design of such trials. First, while MS patients report that marijuana relieves spasticity, it negatively affects their ability to balance, exacerbating another symptom of the disorder. It may be that patients would become tolerant to the balance-impairing effects of cannabinoids relatively quickly yet continue to get relief from spasticity. It might also be possible to separate these effects by creating chemical variants of natural cannabinoids. Second, human trials should rule out any masking or enhancing effect of anxiety reduction due to THC, since anxiety worsens spasticity in many patients.

If THC or a related compound does prove to relieve spasticity, it would make sense for some patients to take the drug orally. In this way patients could take advantage of THC's ability to remain active in the body for several hours. People with spinal cord injury, whose symptoms vary little throughout the day, could get extended relief from a pill taken at bedtime or in the morning. On the other hand, MS patients might find more use for an inhaled form of THC to relieve their more intermittent symptoms. Unlike pills, this delivery method would allow patients to feel the drug's effects quickly and with a minimum of sedation. At nighttime MS patients might actually prefer pills that cause drowsiness as well as relieve spasticity.

People with MS may soon be able to test a cannabinoid inhaler if the previously described British clinical trials receive funding. Additional trials may take place in Canada, where in July 1999 the government issued a request for research proposals to study medical uses of marijuana. While the official announcement did not prescribe specific research topics, it mentioned multiple sclerosis as a possible subject for a clinical trial.

NOTES

1. Malec J, Harvey RF, Cayner JJ. 1982. “Cannabis effect on spasticity in spinal cord injury.” Archives of Physical Medicine and Rehabilitation 63:116-118.

2. Consroe P, Musty R, Rein J, Tillery W, Pertwee RG. 1997. “The per-



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