Chronic Pain and Medical Cannabis
Chronic pain affects tens of millions of people around the globe, and it is perhaps the most widely spread disease condition in existence. For thousands of years, humans have attempted relief from pain utilizing a multiplicity of therapies and techniques to reduce or mitigate pain. Cannabis has a long history of being used by many ancient societies, and over 5,000 years ago was used by the Chinese as a surgical anesthesia, and also in ancient Israel as an aid to the pain of childbirth. Egyptian, Roman, Greek, and African civilizations have also used cannabis for pain relief and to improve the well-being of its citizens. Previous to 1939, The United States Pharmacopeia also employed cannabis tinctures and balms, as the treatment of pain was a common use of cannabis before it’s prohibition and banning from society. Cannabis was used for many types of pain including digestive pain, headaches, neuralgias, menstrual cramps, migraines, and other types of inflammatory or chronic pain conditions. After its prohibition and stigmatization, and the rise of pharmaceutical drugs, cannabis was no longer employed and all but disappeared as a treatment to combat pain, and was subsequently removed from the US Pharmacopeia.
Pain is very subjective for each individual, and what works for pain in one person may be ineffective in another. While there are many types of pain, generally pain is classified as nociceptive or neuropathic, with nociceptive pain being short-lived and caused by environmental insult or trauma (think bee string or cut or scrape), and neuropathic pain directly arising from the nerves themselves and as a result of a chronic disease or condition (i.e. multiple sclerosis, diabetic neuropathy). Failure to treat chronic severe pain can lead to adverse consequences including depression, despair, and even death or suicide. Current attempts to control pain in our country mainly utilize prescription pharmaceuticals and over the counter medications that can cause adverse side effects and damage the liver, stomach, or other major organ systems. Narcotics have been pushed on our society by the drug and pharmaceutical industry, and physicians as a cure-all and common treatment for all types of pain, with sometimes devastating results. Excessive use can easily lead to addiction, respiratory depression, adverse side effects and ultimately death in some instances. Let’s explore the mechanisms and modes of action of some of the cannabinoids in treating neuropathic or chronic pain. Keep in mind that there are over 600 compounds in the cannabis plant and quite a few of these compounds can play a role in counter-acting and alleviating pain. The research will explode on cannabinoids and pain once the federal government allows proper clinical studies. In the meantime, ancient techniques as well as other countries' research can hold additional clues to how cannabis can be effective, especially when other pain medicines fail to achieve a reduction or diminishment of pain.
There is a multitude of pathways and mechanisms whereas cannabinoids can be useful in pain control, and these include cannabinoid receptors located on cell membranes such as the CB1, CB2, PPAR, 5 HT1A, and the GPR 55 receptors, to name a few. Every individual must experiment and use several ingestion techniques, strains, dosages, and products to see what works best.
There is a complex interplay among receptors and everyone has different chemical affinities and regulation of receptors. As mentioned, every patient is different although there are some universal guidelines applicable to the majority of patients seeking pain relief by using cannabinoids. Other components of the plant, including terpenes and flavonoids, may also play a role in pain control. The medical cannabis in Maryland can be construed as being somewhat disappointing as far as being optimized for pain, as much of it is focused solely on high THC content with the exclusion of other cannabinoids and compounds useful to treat pain. Here we are talking about other cannabinoids such as CBC, CBD, CBG, THCA, CBDV, etc.… as well as some terpenes such as beta caryophyllene, myrcene, and others. Much of the cannabis flowers produced in our state lack many of these ingredients, and for this reason, sometimes concentrates, edibles or tinctures can be employed for optimum control of pain which have a broader and more full cannabinoid profile than most of Marylands flowers. However, it is also true that THC is one of the main cannabinoids useful in the control of pain, muscle spasms, and muscle tension.
Cannabinoids are known to have direct neural modulation effects via neurotransmitters and various receptor-based mechanisms in the nervous system. One common effect is the reduction of neural transmission from one nerve cell to the next to eliminate excessive neuronal firing through retrograde inhibition. In this case, a postsynaptic neuron will feedback to a presynaptic neuron to stop its firing and transmission of the pain signal. This happens at multiple levels in the central nervous system, peripheral nerves, and also in the brain in both descending and ascending pain pathways. Exogenous cannabinoids can act to regulate and decrease neural impulses of pain thru binding to the receptor site on the presynaptic neuron and eliminating the synaptic release of chemicals transmitting the painful impulse between nerve cells.
Research has shown that there is some overlap of the opioid system and mu-opioid receptors with the CB1 and CB2 receptors that mitigate the pain response. However, in some studies, the use of cannabis for neuropathic pain is equal or MORE effective than codeine or morphine in reducing pain and fewer side effects. THC has been shown in clinical studies to increase the effectiveness of morphine, thereby allowing a lower dose of the narcotic to achieve the same level of pain control. In fact, often the dose of narcotics used can be cut in half almost immediately if also using concurrent cannabinoids. THC has also been shown to act on the kappa and delta-opioid receptors whose stimulation acts synergistically with opiates. One issue of concern is that if the THC concentration is too high then adverse psychoactive effects can be experienced. These effects are not life-threatening but can be undesirable by the user and require techniques to offset them via dosages, ingestion techniques, or the use of concurrent CBD. This perceived negative effect caused by excessive THC is more pronounced in naïve or inexperienced users, and a certain tolerance can be developed with repeated use over a few weeks to lessen adverse effects.
Systemic use of the cannabinoids have been shown in animal and human models to suppress behavioral reactions to acute noxious stimuli that can cause pain, and also reduce inflammatory pain and pain from nerve injury. Most of this reduction in nociceptive pain comes from CB1 receptor stimulation either by anandamide (your body’s own cannabinoid) or from THC ingested from the cannabis plant. CB2 receptor stimulation is more common in neuropathic pain control in the peripheral nerves, and is also activated by THC. The CB1 and CB2 receptor stimulation also helps to prevent the release of pro-inflammatory cytokines, and also stimulate the mu-opioid receptors as well as stimulate the release of the endogenous opioid beta-endorphins. Cannabis has been shown the work in intractable pain syndrome and treats neuropathic pain where opioids were ineffective. Some studies indicate that 20 mg THC is as effective in pain control as 120 mg of codeine. In instances of pain from muscle spasms as in MS, for example, cannabis is also effective in moderating pain, reducing the progression of the disease, and reducing neuropathic pain, and aiding in sleep.
CBD also plays a major role in pain control along with THC. CBD can play a role thru its action on several other receptor sites other than CB1 and CB2. In fact, CBD stimulates the 5-HT1A receptors, the glycine alpha—3 receptors, and the TRPV1 receptors that assist in the spinal control of pain. CBD is highly anti-inflammatory and reduces the degradation of anandamide and prolongs the effect of the THC to provide longer relief of pain. CBD is particularly effective in diabetic neuropathy, and in the use of pain experienced with Multiple Sclerosis. Lower doses of CBD also promote sleep in some individuals, whereas a higher dose can be stimulating – and this biphasic effect is quite common with CBD.
Patient control of pain using cannabinoids can be thru ingesting tinctures, edibles, vapes, smoking, transdermal patches, pills, troches, or creams and lotions topically applied. Patients are advised to try as many types, strains, dosages, and delivery techniques as they have available until they find the best one for their particular pain. Quite often, the sedation and sleep-inducing nature of cannabinoids alone can reduce or treat pain, by allowing a full night of restorative sleep, without being awoken from pain. In addition, cannabis has been shown to be a mental distractor by shifting thought patterns away from all-encompassing pain and allowing other more positive thoughts to develop and suppress pain modulation, and to deter negative feelings associated with chronic pain.