Doctors prescribe marijuana for various conditions. Pain, however, remains the number one reason for prescription for almost 91 percent of users across seven states. According to a 2014 paper published in The Journal of Global Drug Policy, cannabis can alleviate both acute and chronic pain. Acute pain is short-term and lasts only until the injury is healed, while chronic pain persists for more than three months, such as in cancer and arthritis.
Inadequate Pain Relief
About 38 million adults in America suffer from chronic pain, and 12 million of them have turned to marijuana for relief, according to an ABC News poll. The usual armamentarium of analgesics for chronic pain--from opiates to antidepressants and anticonvulsants--are no longer adequate, especially in intractable cases such as cancer-associated pain and neuropathic pain, which is caused by damaged nerves. In a recent patient non-adherence study by Ameritox, urine samples were collected from patients who were prescribed hydrocodone, one of the most frequently prescribed opioids. Of the urine samples that tested positive for marijuana, 36.5 percent showed no traces of the prescribed hydrocodone. "…the data strongly suggests that marijuana use is associated with an increased...prescription non-drug adherence," said Harry Leider, MD, Chief Medical Officer of Ameritox. This non-adherence indicates that people who are using cannabis are finding relief from their pain without opioids.
How Cannabis Helps
To equip physicians with better pain management tools, researchers are taking another look at cannabis, which has been used against pain for more than 2,000 years. It has been discovered that the main cannabinoids in marijuana, such as THC (delta-9-tetrahydrocannabinol) and CBD (cannabidiol), are similarly structured to the body's own endocannabinoids (neurotransmitters that produce pain relief). This allows THC and CBD to bind to cannabinoid receptors in the body and elicit analgesia. The non-psychoactic CBD also helps by reducing nausea, decreasing anxiety, suppressing seizures, and inhibiting the synthesis of pro-inflammatory proteins, making marijuana an effective anti-inflammatory agent as well.
Cannabinoid receptors are located in different areas of the body, but when it comes to neuropathic pain, those that are situated in the rostral ventromedial medulla (RVM) part of the brain play possibly the most critical role. Scientists in Italy were able to confirm that two non-psychoactive cannabinoids--CBD and cannabichromene (CBC)--in marijuana have successfully targeted the RVM in rat models. The findings confirm the viability of marijuana in treating neuropathic pain induced by cancer, HIV infection, alcoholism, diabetes, shingles and amputation, to name some.
On the Right Track
In fact, Sativex, a new cannabis-derived drug that contains equal parts THC and CBD, is already approved in Canada for the treatment of neuropathic pain in multiple sclerosis and cancer. Its safety and efficacy are demonstrated in several clinical trials, including for rheumatoid arthritis. Possible adverse effects, like tiredness and dizziness, are noted to be acceptable. Sativex has been granted Fast Track Designation by the US FDA, to expedite its development and review for the treatment of advanced cancer in patients who experience inadequate relief despite optimized opioid therapy.
The recognition of cannabis as a powerful agent in pain management is spreading throughout the country. Medical marijuana is already legalized in 23 states and in Washington DC, while more than half a dozen are pending legislation.