Today, about half of patients with cancer seek cannabis support for symptoms during treatment or as survivors. Most end up self-medicating, using sub-optimally (or even unsafely) and overspending on products. Some shouldn’t be using cannabis at all. 



For these reasons, before beginning treatment we recommend you review the benefits and risks of cannabis care for cancer-related symptoms and consult with your oncology team and/or primary care doctor.

A growing body of research supports the efficacy of cannabis for various cancer and treatment-related symptoms such as pain, chemotherapy-induced nausea, and poor appetite.

The management of cancer pain specifically is a significant challenge for the medical community. Many patients can end up cycling through multiple treatments with trial and error at a time when the need for addressing symptoms may be acute. Fortunately, there’s growing evidence that guided cannabis care can improve control of various pain associated symptoms including cancer pain.[1-4]

Cannabis can be effective against cancer pain due to its analgesic and anti-inflammatory compounds, which can reduce pain sensations directly or indirectly by interaction with various receptors throughout the body.[5]

Newer areas of promise include the management of neuropathic/nerve and migraine pains from causes such as chemotherapy.[6,7] Cannabis can reduce pain and sensitivity without targeting vessels in the head as traditional migraine medication does. Instead, cannabinoids interact with nerves and receptors in the brain to reduce migraine symptoms. Recent reviews and meta-analyses provide promising evidence cannabis may be successful in relieving neuropathic pain. A recent meta-analysis provided additional evidence cannabis may be effective in relieving this type of pain.[8]

Moreover, patients with cancer pain whose symptoms could not be adequately relieved by traditional painkillers seem to respond well to supplemental cannabis treatment.[9]

Importantly, cannabis can also be used to reduce and even replace many prescription pain medications such as opioids and sedatives. Recent US data demonstrated that opioid-related mortality is lower and prescriptions for opioids have declined more significantly in states with legal access to cannabis. [10, 11] In addition, a growing number of studies report that cannabis has a better side effect profile compared to narcotics and a lower risk of dangerous addiction. [4, 12, 13] The clinical evidence supports these preliminary findings; many regular cannabis consumers find that cannabis therapies help to prevent the need for more pharmaceuticals with higher addictive potential.

Cannabis has also shown potential as a pain reliever when used instead of, or together with, common anti-inflammatory drugs (e.g., Advil, Motrin, etc.) as these medications all amplify the body’s production of anti-inflammatory prostaglandins, which can be associated with risk to sensitive organs, particularly when taken consistently over long periods.

Nausea and poor appetite in patients with cancer presents another challenge to the medical community. Fortunately, many patients report that cannabis relieves chemotherapy-induced nausea, and a growing body of clinical evidence supports these anecdotes.[14-18] Recent research also showed that patients preferred cannabis over other anti-nausea and anti-vomiting treatments.[19, 20]

In addition, cannabis has shown potential as a tool to help stimulate appetite in patients with cancer. Appetite improved in several randomized studies in patients with cancer.[21, 22] Small studies have showed both improved appetite and slowed weight loss.[23, 24] While research to date is promising, future studies will help to better understand and evaluate the use of cannabis in appetite stimulation.

Current evidence suggests that cancer pain treatment with cannabis is less habit-forming and non-lethal compared to traditional medical alternatives.[25] Unlike other drugs, cannabinoids don't suppress the receptors that control essential lung and heart function, so there's less risk of fatal overdoses.

However, it’s important to know that cannabis products contain compounds such as THC and CBD, which may interact with prescribed medications.[26,27] Those interactions can be potentially dangerous, increase or decrease prescription medication efficacy, and might have adverse effects as a result.

These medications include antibiotics such as Erythromycin, cardiac medications such as Diltiazem and Verapamil, seizure medications such as Clobazam, antiviral medications such as Ritonavir, and life-saving blood-thinning medications such as Warfarin.[26, 27] Potential medication interactions are just one reason an expert cannabis clinician should always provide cannabis care.

Other possible side effects of cannabis can include fatigue, diarrhea, changes in appetite, and changes in weight.[28] For some patients, these symptoms can be alarming and confusing, as they can often occur in association with symptoms of both chronic and acute illnesses.

While relatively benign relative to other pharmaceuticals and over-the-counter medications, the presence of cannabis medications in the bloodstream can have other measurable impacts. Cannabis can cause reversible liver enzyme increases, both alone and in combination with pharmaceuticals. When consumed in large amounts, cannabis can impact cognitive function in the short term, including memory and processing capabilities. For those who consume cannabis by inhalation, a recent European report found that cannabis use may lead to more frequent bronchitis if smoked on a regular basis.

Another common impact and potential concern is cannabis can increase heart rate and either raise or lower blood pressure. These effects may impact frail, older adults with balance issues, who may have an increased risk of dizziness and falling when using cannabis.[29]

The persistent and sustained excessive use of cannabis can also have longer-term effects. Many people consuming cannabis daily and in large volumes report that they feel slower, think less clearly, and can recall information less effectively than when they consumed less or none at all.

And of course, anyone using THC/intoxicating cannabis products should refrain from driving, operating heavy machinery, or any other activities in which intoxication might pose a health or safety risk to themselves or others.

Adolescents, individuals outside of active medical care with a history of psychotic, mood or anxiety disorders, women who are pregnant, or planning to be pregnant, and people with cardiovascular diseases should only consider cannabis care in consultation with a licensed cannabis clinician.[29]

There are a number of ways cannabis works to address cancer associated symptoms such as pain, nausea and poor appetite.

Both THC and CBD affect CB1 and CB2 receptors directly or indirectly. CB1 receptors are found in the brain, while CB2 receptors are found in the peripheral nervous system. THC is known to work on the CB1 receptors, with the potential for euphoric effects, whereas CBD is known to work on CB2 receptors, which is not associated with euphoric effects.

THC and CBD can regulate pain thresholds at the site of pain origin to help manage the strength of pain signals propagated by the receptors responsible for detecting pain. In addition, cannabinoids function as anti-inflammatories, inhibiting pain messenger production. Moreover, cannabis can change how pain signals are transported to and received by the brain, at so-called mu-opioid receptors, which is one reason cannabis can be used to replace opioids.

In addition to its effects on nerves and signal transmission, cannabis modulates other aspects of the endocannabinoid system, including regulating stress levels, encoding long-term memory, and promoting physical and emotional homeostasis. If the body isn't making enough cannabinoids or if the innate cannabinoid receptors (CB1 and CB2) aren't functioning optimally, pain signals may not be adequately inhibited, and pain and suffering may increase. Besides THC and CBD, other minor cannabinoids (such as CBN,CBC, THCA or CBG), may also have pain-killing properties and make an equal contribution to overall pain relief.

Cannabis has also been shown to modulate the endocannabinoid system to help alleviate chemotherapy-induced nausea and vomiting. The CB1 and CB2 receptors are associated with control of nausea and vomiting. Both THC and CBD help suppress nausea and vomiting in patients with cancer by interacting with these receptors. In a parallel process, cannabis may also modulate a key neurotransmitter associated with chemotherapy-induced nausea and vomiting to help alleviate symptoms.

There is also evidence that cannabis modulates the endocannabinoid system to stimulate appetite. The endocannabinoid system regulates eating behavior through several pathways in the brain and body. These pathways modulate ghrelin, leptin, and other peptides associated with appetite regulation. Medical cannabis and THC specifically may help alleviate poor appetite in patients with cancer by interacting with CB1 receptors.

The endocannabinoid system also regulates eating behavior through several pathways in the brain, limbic system, intestinal tract, and adipose tissue. Cannabis has been shown to interact with CB1 and CB2 receptors to stimulate appetite, though more research among patients with cancer is needed to fully understand how cannabis works to stimulate appetite.

There is growing evidence that the endocannabinoid system also helps regulate nausea and vomiting.[26] CB1 and CB2 receptors are associated with both nausea and vomiting control, and both THC and CBD appear to modulate these receptors to suppress symptoms of nausea that patients with cancer may experience.

The endocannabinoid system also regulates eating behavior through several pathways in the brain, limbic system, intestinal tract, and adipose tissue. These pathways modulate peptides involved in appetite regulation such as ghrelin and leptin. Cannabis has been shown to interact with the endocannabinoid system and stimulate appetite.

What is the endocannabinoid system? It’s complex—and rarely taught in medical school. But it can be helpful to think of the endocannabinoid system as one of the body’s master regulators.

Briefly stated, it’s a neuroregulatory system that keeps physiologic functions in balance or homeostasis. It plays a crucial role in inflammation, immune response, pain detection, the sleep-wake cycle, mood, memory, appetite regulation, reproduction, and fertility. It consists of three major components: naturally produced chemicals (self-made endocannabinoids acting as transmitters), the receptors those endocannabinoids bind to (located on neurons, immune cells, etc.), and the enzymes which synthesize and degrade these components.

The human body uses two naturally derived signaling molecules called endocannabinoids: anandamide (aka the bliss molecule) and 2-arachidonoylglycerol (2-AG). Endocannabinoids are structurally similar to, but distinct from, the cannabinoids found in cannabis plants, though they act on the same receptors.

Cannabinoids derived from plants are usually referred to as phytocannabinoids. These plant-based cannabinoids consist of a wide variety of active cannabinoid molecules, with nearly 150 discovered to date. The best known molecules are tetrahydrocannabinol (THC), tetrahydrocannabinol acid (THCA), cannabidiol (CBD), cannabigerol (CBG), or cannabinol (CBN).

In addition to these 150 cannabinoids, the cannabis plant produces hundreds more organic compounds called terpenes and flavonoids. These unsaturated hydrocarbons may not activate the endocannabinoid receptors directly, but they modulate and fine-tune the functions of the activated receptors. This effect (of interaction with the receptors and molecules is known as the "entourage effect."

The second component of the endocannabinoid system is the cannabinoid receptor. The biological effects of cannabinoids are controlled by dozens of known cannabinoid receptors, the most relevant being receptors 1 and 2. Cannabinoid receptor 1 is primarily located in the brain, while cannabinoid receptor 2 is present exclusively in immune cells throughout the body. If an endocannabinoid binds to a cannabinoid receptor 1 in the brain, it may help to relieve pain. In contrast, an endocannabinoid that attaches to the cannabinoid receptor 2 in the immune system might help relieve symptoms of inflammation; it can tone down pro-inflammatory markers like cytokines and interleukin.[30]

The third component of the endocannabinoid system are enzymes, which synthesize and break down endocannabinoids. While many enzymes keep the endocannabinoid system balanced, the ones of therapeutic interest are the fatty acid amide hydrolase (FAAH) and the monoacylglycerol lipase (MAGL). The body's endocannabinoid response can be improved by modulating these enzymes for therapeutic purposes.[31] As a result, the endocannabinoid system keeps our body balanced, and cannabis can help support its natural function.

As the evidence grows, it’s increasingly clear: An ongoing partnership with a clinician is essential in order to use cannabis safely and optimally in the treatment of anxiety.[20-25]

An EO clinician or other expert cannabis clinician with a thorough understanding of your goals, medical record, current medications, and cannabis use history should be involved in formulating initial and ongoing product recommendations, doses, and times of use.

Expert clinical oversight is essential for anyone seeking relief through cannabis. Here’s why:

Safer and more optimal pain relief through cannabis can only be achieved with a personalized care plan that factors in the symptoms and causes of your pain, relevant aspects of your medical record, your cannabis use history, other medications you’re using and your daily schedule.

A period of “test and learn” is typically necessary to arrive at the products, doses and times of use that are most right for you.

Even after achieving a regimen with which you’re satisfied, changes to your medical condition, your cannabis tolerance, daily schedule and shifting product availability all mean your care plan will need to be periodically modified over time in order to maintain high levels of safety and efficacy.

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