According to a study by researchers at the University of California, San Diego (UCSD) Center for Medical Cannabis Research, marijuana in moderate amounts decreased neuropathic pain by as much as 34% in two subjects. Small amounts of cannabis had no effect on pain, and at high levels, pain actually increased.
In another study from San Francisco General Hospital, smoked marijuana was associated with ≥30% reduction of average daily neuropathic pain in 10 of 16 experienced marijuana users with neuropathy due to HIV, nucleosides, or both.
Recently, results of a new study suggest that people with chronic neuropathic pain are twice as likely to smoke cigarettes as those who have chronic nociceptive pain. Why is this? Research studies have found a link between nicotinic receptors and acetylcholine receptors in the spinal dorsal horn, which are actively involved in the perception of pain.
Nociceptive pain is the common discomfort experienced as a result of injury, such as a broken bone or appendicitis. The pain is a message sent from peripheral nerves to the spinal column and on to the brain, signaling injury. The pain is typically well localized, constant, and often with an aching or throbbing quality. Nociceptive pain typically responds to anti-inflammatory agents and opiates.
Neuropathic pain is associated with injury to a nerve or the central nervous system. Such injuries can give rise to paresthesias, such as numbness, tingling, or electrical sensations. Among the many causes of peripheral neuropathy, diabetes is the most common, but the condition can also be caused by chronic alcohol use, exposure to other toxins, vitamin deficiencies, nerve entrapment and sympathetically mediated pain. Neuropathic pain often responds poorly to anti-inflammatory agents and opiates.
The possible physiologic relation between nicotine and treatment of chronic neuropathic pain deserves further evaluation. But bear in mind that in the scientific community conducts this research with nicotinic drugs that are ingested or injected, not with inhaled nicotine. The adverse risks of smoking outweigh any potential benefits of pain relief.