Chronic pain is by far the most common indication for medical cannabis prescriptions in Australia. In 2016, the Australian federal government legalized medical cannabis. Since then, over 200,000 approvals for medical cannabis products have been granted. Most were for non-cancer-related chronic pain.
There is evidence to support the use of cannabis pharmacotherapy for chronic pain patients in certain clinical scenarios.
Depending on the causes of pain your doctor may prescribe a CBD dominant formulation or a balanced CBD and THC formulation.
For inflammatory pain, doctors usually start with a CBD dominant formula. If that doesn’t work they will then suggest a balanced formulation.
For neuropathic pain, doctors will often start with a balanced formula containing equal parts THC and CBD.
If you would like to discuss using medical cannabis to help with your chronic pain you can book in a consultation with our medical cannabis doctors here.
Cannabis for Chronic Pain: Mechanisms of Action
Chronic pain can be defined as pain that is ongoing and usually lasts longer than six months. It’s one of the most common reasons patients see their doctor.
Patients with chronic pain often get prescribed opioids, but these drugs can cause intolerable side effects and carry the risk of addiction. Patients in Australia are increasingly turning to medical cannabis as an alternative solution where conventional treatments have failed.
Cannabis is a plant with a long history of human use. The active ingredients in the cannabis plant are called cannabinoids. Our body actually produces its own cannabinoids (called endogenous cannabinoids or endocannabinoids). Cannabinoids that come from the cannabis plant are called Phyto cannabinoids.
The main Phyto cannabinoids, THC and CBD, are found in the leaves, flowers, and resins of the cannabis plant. They interact with cannabinoid receptors in our body, which form part of our endocannabinoid system. This process produces therapeutic effects, offering relief from pain, anxiety, depression, and inflammation.
The Endocannabinoid System (ECS) and Pain
The ECS plays a significant role in the perception of pain. Research shows the ECS controls how you sense, and process pain signals sent from the periphery to your brain. It works by regulating the release of serotonin, dopamine, and other compounds from nerves.
“Serotonin has a major role in modulating pain perception. Serotonergic drugs are used in the treatment of migraine headaches and combined serotonin-norepinephrine reuptake inhibitors have been used in chronic pain management (such as fibromyalgia).”
The ECS also activates or inhibits pain perception through spinal cord signaling. When your body is in pain, reports show that cannabinoids decrease your sensitivity to it. Your tolerance lessens, and you can focus on the tasks at hand.
The Endocannabinoid System and Phyto cannabinoids
Medical Cannabis for Inflammatory Pain
Inflammation is one of the most common pain types. Common causes can be from an injury, illness, or a virus, and this pain can also be caused by arthritis, an inflammatory autoimmune disorder that causes pain and stiffness. Inflammation is widespread among fibromyalgia, nonspecific back pain, and osteoarthritis.
Research shows cannabis may help with inflammatory conditions by reducing pro-inflammatory cytokines molecules in the body and thus, reducing pain sensitivity.
Medical Cannabis for Arthritis
There are many forms of arthritis, some that affect people following traumatic injuries, and as they age and the cartilage between their joints wears down.
Another form is rheumatoid arthritis. This condition is an inflammatory autoimmune disorder that happens when your body’s immune system attacks your joints. The disease causes inflammation, swelling, and pain in the joints and surrounding soft tissue. This condition leads to stiffness and difficulty moving.
“In addition, the non-psychotropic cannabinoid, cannabidiol (CBD) demonstrated antiarthritic effects independent of cannabinoid receptors. In addition to controlling inflammation, cannabinoids reduce pain by activating central and peripheral CB1, peripheral CB2 receptors and CBD-sensitive non-cannabinoid receptor targets.”
Treating any arthritis is a complicated process that can take months or years. It may require physical therapy, alternative therapies, and/or pain medications. Some physicians prescribe medicines to help reduce inflammation and pain.
Medical cannabis could be an alternative solution when conventional treatments have failed due to its anti-inflammatory effects. The plant contains cannabinoids that bind to CB1 receptors in the joints. Research shows these receptors influence the immune system to prevent it from attacking healthy tissue and normal joint processes, thus reducing inflammation and pain.
Topical Medical Cannabis for Arthritis
Topical and transdermal cannabis products show promise for patients with arthritis. These methods for using the potent plant involve a local application of a cream or patch that doesn’t break the blood-brain barrier. A 2018 study found,
“Furthermore, research into cannabinoid delivery systems is growing and a plethora of patents have shown interest in the companies working in this field, especially when it comes to local/transdermal administration. Combining formulations may provide an opportunity to produce rapid systemic effects and long-term outcomes (e.g., analgesia). This could be achieved with intranasal cannabinoid sprays used as a low-dose adjuvant to patches in order to aid rapid absorption for systemic effects. Interesting and promising transdermal administration results can also be found in the use of terpenes (from the same source) as CBD and THC penetration enhancers, and thus improve the effectiveness of the therapeutic components.”
Medical Cannabis for Endometriosis Pain
Endometriosis is a chronic, painful disorder that happens when the uterus tissue grows outside of the organ. This tissue grows around the pelvis, lower abdomen, and bladder. The condition also affects fertility and can cause pain during intercourse.
Doctors prescribe nonsteroidal anti-inflammatory drugs for pain relief. These drugs work by inhibiting enzymes that cause inflammation and pain. Some patients also find it helpful to take anti-inflammatory supplements like fish oil and turmeric.
As mentioned above, our ECS regulates pain, inflammation, and immune response in the body. Studies show that when THC binds to the receptors in our ECS, it can inhibit body functions that cause inflammation and pain. One study concluded:
“The interactions between the ECS and pain associated mechanisms in endometriosis patients occur at several levels: changes in central and peripheral neural system, involvement of neuropathic and inflammatory pain, psychological interaction with the pain experience, hormonal variability of the pain, and the expression of cannabinoid receptors, enzymes, and ligands.
Pain management for patients with endometriosis needs to be more effective, target the hormonal and immunologic environment, downregulate proliferation while enhancing apoptosis, and normalize the invasive mechanisms and neo angiogenesis processes. ECS modulation appears to be a good therapeutic strategy by potentially combining all these factors”.
Medical Cannabis for Autoimmune Diseases
Autoimmune diseases happen when the immune system goes haywire and attacks healthy tissue. An autoimmune disorder can cause pain without inflammation, like in neuropathic conditions.
Some autoimmune conditions include rheumatoid arthritis, inflammatory bowel disease, irritable bowel syndrome, and multiple sclerosis. These diseases can cause pain in the joints and muscles.
Research suggests cannabinoids work better for neuropathic pain than opioids or NSAIDs. A recent review of cannabis for autoimmunity found,
” … emerging knowledge of autoimmunity and the high density of CB2 receptors on immune cells makes the endocannabinoid system a natural target for the treatment of inflammatory and autoimmune diseases. “
Medical Cannabis for Fibromyalgia
Fibromyalgia is a chronic neuropathic disorder that causes widespread pain in the soft tissues, muscles, and bones. The condition also comes with other symptoms, like fatigue and sleep problems. Patients who have fibromyalgia often get prescriptions for opioids or use over the counter NSAIDs for pain relief. However, these drugs can often result in many unwanted side effects. The risk of addiction is also high.
CBD is a non-psychoactive Phyto cannabinoid that has been shown to have anti-inflammatory and pain-relief effects. Research shows CBD can block the enzyme that produces inflammation and pain in the upper spinal cord. The compound can also inhibit prostaglandin E2 (PGE2) and leukotriene B4 (LTB4).
THC and CBD interact with CB1 and CB2 receptors in the body. THC binds with CB1 receptors in the central nervous system, which can have psychoactive effects, and CBD has little to no effect when the compound attaches to CB1 or CB2 receptors. However, when the Phyto cannabinoid connects to CB2 receptors in the immune system, it can reduce inflammation and stop pain.
Medical Cannabis For Migraines
Migraines are often treated with nonsteroidal anti-inflammatory drugs to reduce pain, nausea, and light sensitivity. Doctors may also prescribe triptans for migraine relief if over-the-counter medications don’t work. Triptans reduce pain and sensitivity by narrowing the blood vessels in the head.
Medical cannabis can also reduce pain and sensitivity, but it doesn’t target vessels in the head. Instead, cannabinoids interact with CB1 receptors in the central nervous system to reduce nausea and vomiting. Research suggests combining opioids and cannabinoids can reduce migraines better than just opioids. One study concluded:
“Both active cannabis and a low dose of oxycodone (2.5 mg) were sub-therapeutic, failing to elicit analgesia on their own; however, when administered together, pain responses as measured by the CPT were significantly reduced, pointing to the opioid-sparing effects of cannabis. Oxycodone did not significantly increase cannabis self-administration. However, the combination of 2.5 mg oxycodone and active cannabis produced modest increases in positive subjective ratings related to oxycodone.”
Medical Cannabis For Knee Pain
Chronic knee pain is a common problem among people over 50 and sports players. Other causes include obesity, arthritis, and injury. NSAIDs like ibuprofen and naproxen can relieve pain and reduce inflammation. However, these drugs may come with side effects like internal bleeding and ulcers. Opioids are another option for knee pain, but they come with risks of addiction and overdose.
Cannabinoids interact with CB1 receptors in the endocannabinoid system. When THC binds to CB1 receptors, the compound can reduce pain and inflammation in the joints. CBD also interacts with CB2 receptors in immune cells, reducing inflammation. Patients can take both compounds in cannabis for knee pain.
Studies concur. A 2017 report explains:
“Natural Phyto cannabinoids and synthetic derivatives have produced clear activity in a variety of models of joint pain in animals. These effects are the result of both inhibition of pain pathway signaling (mostly CB1) and anti-inflammatory effects (mostly CB2). There are also numerous anecdotal reports of the effectiveness of smoking cannabis for joint pain.”
Medical Cannabis for Neuropathic Pain
Physicians often treat neuropathic pain with tricyclic antidepressants, anticonvulsants, and opioid drugs. Antidepressants can take weeks to work, so patients suffering from nerve pain may need faster relief. Tricyclic antidepressants like amitriptyline are common treatments because they effectively reduce neuropathic pain. However, many patients report side effects like drowsiness, dry mouth, and constipation.
Nausea is another common symptom of neuropathic pain. The primary treatments for nausea are dopamine antagonists, and two examples are metoclopramide and prochlorperazine. Side effects include mild sedation, muscle stiffness, dizziness or lightheadedness, and increased appetite.
Cannabis could be an alternative option for reducing neuropathic pain and nausea if these drugs are ineffective or cause intolerable side effects. THC, CBD, and other cannabinoids may reduce neuropathy symptoms like pain and nausea. They also interact with receptors to reduce inflammation and promote sleep, which can help relieve painful symptoms.
“Our responder analysis compared the proportion of patients with an at least 30% reduction in chronic pain as minimally clinically important difference, a meaningful improvement at the individual patient level for about one in every five to six patients treated.”
Does Medical Cannabis Work for Chronic Pain?
Cannabis could be a potentially safer pain alternative for patients with autoimmune disorders, chronic pain syndromes, and other conditions. CBD is a non-psychoactive Phyto cannabinoid that has anti-inflammatory and pain-relief effects. THC can also reduce inflammation and pain, but the compound may also cause psychoactive effects.
A clinical review in the Cannabis and Cannabinoid Research Journal advises,
in certain clinical scenarios. For example, if a patient with chronic pain and their healthcare provider work together through first- and second-line treatment modalities without success, a trial of cannabis or a cannabinoid may be a reasonable next step. Cannabis pharmacotherapy in certain clinical scenarios. For example, if a patient with chronic pain and their healthcare provider work together through first- and second-line treatment modalities without success, a trial of cannabis or a cannabinoid may be a reasonable next step. "There is evidence, although limited, to support the use of cannabis pharmacotherapy in certain clinical scenarios. For example, if a patient with chronic pain and their healthcare provider work together through first- and second-line treatment modalities without success, a trial of cannabis or a cannabinoid may be a reasonable next step. “ is evidence, although limited, to support the use of cannabis pharmacotherapy in certain clinical scenarios. For example, if a patient with chronic pain and their healthcare provider work together through first- and second-line treatment modalities without success, a trial of cannabis or a cannabinoid may be a reasonable next step. “cannabis pharmacotherapy in certain clinical scenarios. For example, if a patient with chronic pain and their healthcare provider work together through first- and second-line treatment modalities without success, a trial of cannabis or a cannabinoid may be a reasonable next step.“
When you combine the two cannabinoids with the other hundreds of compounds, patients experience relief that’s non-habit-forming with only mild side effects. Some patients find that the effects also reduce their anxiety and discomfort. As more research is available, scientists can develop new formulations for improved pain relief with minimal side effects.
Is Medical Cannabis Use Safe?
Evidence suggests that cannabis is a less habit-forming and non-lethal alternative for treating chronic pain. Cannabinoid receptors don’t interact with the receptors that control lung and cardiovascular function in the brain, reducing the risk of fatal overdose and respiratory depression.
How To Use Medical Cannabis For Pain Management
Medical cannabis comes in various forms with each product having its own benefits. Vaporizing flower has almost immediate onset but a short duration of 2-4 hours. While ingesting oil lasts much longer 4-8 hours but onset takes 1-2 hours. Your doctor will discuss the best option for your condition.
Smoking Cannabis Flowers
Smoking cannabis is a popular method of use but has many downsides. Smoking irritates the lungs and reduces lung capacity. Patients will experience coughing, throat irritation and other respiratory complications.
Patients are advised not to smoke cannabis and should always use an alternative method, such as oils, edibles, or vaping.
Vaporizing Cannabis Flowers
A vaporizer heats cannabis flowers to a lower temperature than smoking. It also doesn’t produce smoke because the heat source never touches the flower. Instead, you get a safe, smooth vapor.
Using a vaporizer reduces the risk of irritation and injury to your airways because you aren’t inhaling smoke. Vaporizers are also an acceptable alternative for patients with COPD or other conditions worsened by smoking cannabis.
Vaporizing has the same onset and duration as smoking without the harsh smoke so there is really no reason to smoke cannabis.
Oils are a good option for patients who are uncomfortable using a vaporizer. You can mix oils into food or drinks or take them alone. It’s recommended to take the oil with foods containing fat (such as peanut butter or yogurt, to help increase absorption.) Oils take a while to kick in – usually 1-2 hours but have the benefit of the effect lasting long – 4-8 hours.
Capsules offer precise dosing and strict ratio formulas many medical patients prefer. If you’re using cannabis for pain, pills can also help you avoid the smell and fuss of vaporizing or oils.
Capsules come in pre-defined dosages so the initial process of titrating up to find your ideal dose may be difficult with capsules. It is recommended to initially titrate using an oil. Then when you have found your ideal dose, switch to capsules for ease of use.
Sublingual medical cannabis for pain control includes tinctures, lozenges, and sprays. Depending on the strength and dose, these take effect within 20 minutes and last for four to six hours or longer. This method works fast because the oil absorbs into the bloodstream through the membranes under the tongue. You also have membranes on the inside of your cheeks that will absorb the oil.
A topical is an application of cannabis on your skin. You can use it with creams, ointments, salves, and lotions. Topicals treat localized pain, so choose this method for specific areas of pain.
You may want to apply a topical before bedtime because they take effect within 20 minutes and last up to four hours for some patients.
Your doctor will help you determine the best product option during your consultation. Ensure you follow dosage instructions carefully and always speak with a doctor before trialing medical cannabis for pain relief.
What Are The Different Formulations for Chronic Pain?
Doctors prescribe medical cannabis using a THC to CBD ratio – the most well-known active ingredients in cannabis. This measurement refers to the amount of tetrahydrocannabinol (THC) and cannabidiol (CBD) in each product. The ideal ratio means you’ll get more of the effects that help your pain without experiencing negative side effects.
Depending on the causes of pain your doctor may prescribe a CBD dominant formulation or a balanced formulation. For inflammatory pain, doctors usually start with a CBD dominant formula. If that doesn’t work, they will then suggest a balanced formulation.
For neuropathic pain, doctors will often start with a balanced formula containing equal parts THC and CBD. Based on efficacy and side effects, doctors will then potentially suggest a different formulation. Some patients take a balance formulation at night and a CBD dominant formulation during the day.
Doctors generally prescribe an oil to start, then if patients experience break through pain, vaporized flower could be a good option given the rapid onset. Your doctor will advise to titrate the oil slowly (start with a low dose and slowly increase each time to achieve the desired therapeutic effect). The aim is to achieve the therapeutic benefits without impairing coordination or motor skills.
As you can see, cannabis is a very individualized medicine which requires the careful supervision of a qualified doctor to manage.
Ensure you obtain medication via the doctor-prescription route as you will receive a lab tested, regulated product, ensuring minimum quality standards. Unregulated, illegally sourced cannabis products have been proven to be low quality and inconsistent.
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