There are many case reports of marihuana smokers using the drug to reduce pain: postsurgery pain, headache, migraine, menstrual cramps, and so on. Ironically, the best alternative analgesics are the potentially addictive and lethal opioids. In particular, marihuana is becoming increasingly recognized as a drug of choice for the pain that accompanies muscle spasm, which is often chronic and debilitating, especially in paraplegics, quadriplegics, other victims of traumatic nerve injury, and people suffering from multiple sclerosis or cerebral palsy. Many of them have discovered that cannabis not only allows them to avoid the risks of other drugs, but also reduces muscle spasms and tremors; sometimes they are even able to leave their wheelchairs.

The years of effort devoted to showing that marihuana is exceedingly dangerous have proved the opposite. It is safer, with fewer serious side effects, than most prescription medicines, and far less addictive or subject to abuse than many drugs now used as muscle relaxants, hypnotics, and analgesics.

Thus cannabis should be made available even if only a few patients could get relief from it, because the risks would be so small. For example, as I mentioned, many patients with multiple sclerosis find that cannabis reduces their muscle spasms and pain. A physician may not be sure that such a patient will get more relief from marihuana than from the standard drugs baclofen, dantrolene, and diazepam -- all of which are potentially dangerous or addictive -- but it is almost certain that a serious toxic reaction to marihuana will not occur. Therefore the potential benefit is much greater than any potential risk.

Dr. Grinspoon is professor emeritus at Harvard University School of Medicine, and the author of numerous publications.

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