Medical Marijuana for Neuropathy Pain
Neuropathy is a general term referring to the conditions that result from the dysfunction of, or damage to, the nervous system. In most cases, the damage affects the peripheral nervous systems (peripheral neuropathy), which lies beyond the brain and spine. Depending on the affected nerves, the damage may impair movement and sensation as well as organ and gland function. In other words, damage to the sensor, motor, and autonomic nerves may produce different symptoms. This condition can affect more than one type of nerve at the same time (polyneuropathy). Neuropathy can be chronic, where symptoms start subtly and progress gradually. It can also be acute, with a sudden onset and fast progression. In this article, we will discuss medical marijuana and how it can be used to alleviate neuropathy pain.
The Causes of Neuropathy
Neuropathy has a wide variety of causes. It can be caused by a genetic disease such as Fabry disease, ataxia, and Charcot-Marie-Tooth disease. It may also be caused by endocrine and metabolic diseases, including diabetes mellitus, liver failure, kidney failure, and hypothyroidism.
Physical trauma, including automobile accidents, compression, sports injuries are another common cause of nerve damage. Certain medications such as metronidazole and fluoroquinolone antibiotics (Avelox, Ciprofloxacin) can also cause the condition.
Other causes include vitamin deficiencies, chemotherapy, excessive alcohol consumption, viral infection, and immune system disease. Neuropathy can also be idiopathic (no known cause).
The Symptoms of Neuropathy
Individuals with diseases of the nerves may exhibit problems with normal nerve functions. The symptoms will vary depending on the type of nerves affected. Regarding sensory function, the common symptoms include pain, numbness, tingling, pins-and-needles, balance impairment, and gait abnormality.
In terms of motor function, pain includes weakness, muscle atrophy, cramps, and tiredness. Chronic pain is one of the most common symptoms of peripheral neuropathy.
According to the Neuropathy Association, about 20 million Americans are afflicted by neuropathic pain. For the people living with neuropathy, the pain is debilitating, often affecting their physical, emotional, and social health.
Current Treatment Options for Neuropathy
The treatment options for neuropathy vary depending on the cause. While treatment of the underlying condition aids in the management of neuropathy, most options aim to alleviate some of the symptoms such as neuropathic pain. The treatment options include:
- Antidepressants – Tricyclic antidepressants such as amitriptyline, nortriptyline, desipramine, and imipramine. Antidepressant treatment has been shown to be mostly ineffective.
- Antiepileptics – Some antiepileptic drugs such as gabapentin provide some pain relief for neuropathic pain associated with diabetes mellitus.
- Opioids – Opioids such as morphine, hydromorphone, and fentanyl can be recommended for patients with severe neuropathic pain.
Unfortunately, the treatment options for neuropathy are challenging, with many patients only obtaining nominally effective pain relief. The commonly prescribed medications come with several unwanted side effects. Opioids are highly addictive and can cause dependency issues.
Medical Marijuana for Neuropathy
With the current options offering little improvements to the quality of life of the affected, patients and researchers are looking into medical marijuana for neuropathy as a potentially effective option. People around the world have used cannabis to treat many painful conditions for centuries due to its natural analgesic properties.
In 2008, researchers examined the efficacy of smoking marijuana on peripheral and central neuropathy pain in 38 patients. The researchers assigned the patients to a high-dose (7 %), low-dose (3.5 %), or placebo group and measured their pain scores sometimes following administering.
The groups that smoked cannabis exhibit significantly reduced pain scores than the placebo group. This study also revealed that the high-dose group experienced great pain relief. However, the higher-dose group did exhibit memory and cognitive impairment.
In a 2010 study, researchers administered cannabis at four potencies (9.4%, 6%, 2.5%, and 0% THC) to 23 patients with postsurgical or post-traumatic neuropathic pain. They discovered that one inhalation of 25 milligrams of 9.4 % THC cannabis three times a day for five days resulted in a reduction of pain intensity, was tolerated well, and improved sleep.
A clinical study conducted in 2015 sought to investigate the effect of smoked cannabis (7 %, 4 %, and 1 % THC) on diabetic peripheral neuropathic pain. The randomized double-blinded crossover study involved 16 patients. The researchers exposed each study subject to four single-dose sessions of high (7 %), medium (4 %), low (1 %), and placebo doses of cannabis.
They then performed evoked pain and baseline spontaneous pain tests. The trial demonstrated that depending on the dosage, cannabis resulted in a significant reduction in diabetic peripheral neuropathic pain. This study added to the body of evidence supporting further research into the efficacy of cannabis in treating different types of neuropathic pain.
A systematic review of 13 clinical studies published in 2017 indicated that across nine studies, patients receiving medical marijuana were more likely to report reductions in neuropathic pain up to 30 %. Although limited, this adds to the body of evidence indicating significant pain relief in some neuropathy patients.
In a 2018 review of research from recent randomized controlled trials (RCTs), researchers examined the potential of medical cannabis as an effective alternative option for neuropathic pain. The studies involved medical marijuana with various THC concentrations and administration routes. Different RCTs showed that medical cannabis was as effective as current pharmacotherapies at alleviating neuropathic pain without having the associated side effects.
The evidence supported the use of low-dosage, short-term marijuana oral delivery, and vaporization for treating neuropathic pain. While more research was recommended to study the long-term efficacy, the review indicated that medical cannabis might be a more tolerable treatment alternative.
Another 2018 systematic review of 16 clinical studies by Cochrane aimed to assess the efficacy, safety, and tolerability of cannabis-based treatments (inhaled cannabis, synthetic THC, and plant-derived CBD sprays) for chronic neuropathy pain in 1750 adults. Through the statistical analysis, the researchers discovered that cannabis-based treatments resulted in reduced pain intensity, psychological distress, and sleeplessness.
The authors of the review stated that medical marijuana helped patients realize a 30 % reduction in neuropathy pain, and even a 50 % reduction, potentially. Note that the authors recommended further large-scale human studies to substantiate the safety of marijuana as a neuropathy treatment alternative.
A systematic review led by Harvard University in 2018 assessed the results of more than 30 studies investigating cannabis and cannabinoid use in treating symptoms of multiple sclerosis, including chronic neuropathic pain. Ten of these studies were of high quality RCTs. The authors concluded that medical marijuana was an effective option for reducing neuropathic pain and stiffness caused by multiple sclerosis.
How Medical Marijuana for Neuropathy Improves Pain
When a nerve gets damaged, there are some activities inside individual nerve cells (neurons) that are changed. As a result, the neurons may become hyperactive or over-sensitive, a process referred to as sensitization.
Ongoing pain receptor input that persists after the damage has healed causes sensitization. The receptor input is caused by neuron activity, such as increased availability of excitable pain receptors and a greater number of excitatory neurotransmitters.
Cannabinoids, especially THC and CBD, are thought to change neuron activity and thus reduce neuropathic pain. THC, for instance, facilitates the increase of beta-endorphins that alleviate pain in a similar manner to opioids.
Cannabinoids also inhibit the neurotransmission of pain in the section of the spinal cord, receiving sensory information. Also, some cannabinoids are associated with the suppression of hypersensitivity of receptors that detect pressure changes (mechanoreceptors) through the activation of CB1 and CB2 receptors.
There is a growing body of scientific and anecdotal evidence supporting the crucial role of medical marijuana for neuropathy pain management. This means that medical marijuana seems like a viable treatment option for individuals that have difficulties tolerating or don’t respond well to conventional medication.
While more research and clinical studies are needed to conclusively determine the efficacy, tolerance, and safety of medical marijuana for neuropathy, the current evidence offers respite to the millions of people afflicted with this debilitating condition.
If you think medical cannabis may help you, schedule an appointment with MMJ Doctors now or call us at 1-888-578-6704.