Chronic pain is common in cancer patients, and it can arise directly from cancer tumors or a side effect of cancer treatment. As the pain has a detrimental impact on a patients’ physical, cognitive, and emotional life domains, appropriate therapeutic measures are critical for cancer patients to restore and maintain their quality of life.
But unfortunately, standard treatment options for end-stage cancer patients with painful or neuropsychiatric surgery rely mainly on opioid analgesics, which can be detrimental for some individuals.
The reason for this could be a combination of factors, such as individual differences in drug reactions and substance-related side effects such as constipation, which could prevent adequate doses of pain relief from being administered.
Furthermore, indiscriminate doses put patients at risk of becoming addicted to opioids or overdosing. As a result, it’s critical to find alternative analgesics that can successfully improve the quality of life in cancer patients.
What makes Cannabis a better Cancer Medication than Opioids?
The poor management of cancer-related neuropathic pain has an adverse influence on a patient’s quality of life.
Patients who cannot tolerate opioid analgesics or experience serious side effects from conventional painkillers should consider alternative therapeutic options.
According to anecdotal reports, medical cannabis has the potential to relieve pain in patients successfully. 
Mechanism of Cannabinoids in Cancer Pain Management
The Cannabis plant, which belongs to the Cannabaceae family, contains more than 100 cannabinoids, of which two main active ingredients are present, i.e,
- THC (tetrahydrocannabinol) has psychoactive characteristics
- CBD (Cannabidiol) is a significant component of cannabis that does not have psychotropic impacts but contains antiemetics, antiepileptic, and other properties.
CB1 and CB2 cannabinoid receptors have been identified in the human body, with CB1 located in the brain and CB2 in the immune system.
CB1 receptors in the CNS and nerve terminals are activated by cannabinoids, which provide analgesic effects. Moreover, peripheral CB2 sites aid analgesia by inhibiting the generation of painful and inflammatory processes, which is critical for cancer pain management.
Effects of cannabis medications on cancer-related symptoms
Dronabinol (a compound containing cannabis cannabinoids) has been shown in several studies to help with chemotherapy-related vomiting and nausea. Dronabinol has been reported to aid in improving food intake and the prevention of weight loss in HIV patients. However, it was no better in cancer patient tests than a placebo or another medicine (megestrol acetate).
Nabiximols have shown effectiveness in alleviating cancer pain that isn’t eased by strong pain relievers, but it hasn’t been found to be effective in all studies. This medication is still being researched.
How Can Cannabis Help Cancer Patients?
Medical marijuana has been studied for its potential to alleviate cancer symptoms and adverse effects after treatment.
Manages post-cancer treatment symptoms
A few studies have found that smoking marijuana can help with chemotherapy side effects. Man-made cannabinoids such as Dronabinol (Marinol, Syndros) and Nabilone (Cesamet) have also been licensed by the FDA to treat similar symptoms when other nausea treatments have failed.
According to several studies, smoking marijuana can help with cancer-related pain. It binds with cannabinoid receptors in the brain and other regions of the body. Marijuana also helps with pain by reducing inflammation.
Nerve injury causes neuropathy, which manifests as weakness, numbness, or discomfort. Chemotherapy or other cancer therapies may cause this to happen. According to a few studies, smoking marijuana can aid with this particular form of nerve pain.
Palliative effects of Cannabis:
Reduced Nausea and Vomiting:
One of the most serious side effects of cancer chemotherapy is nausea and vomiting. Although the administration of antiemetics on a regular basis, chemotherapy-derived nausea, and vomiting (CINV) is nevertheless a common occurrence.
Cannabinoids’ antiemetic properties have been well documented in animal studies. Antiemesis is thought to be caused by cannabinoids blocking acetylcholine and reducing digestive tract movement or by binding on CB1 sites in the dorsal-vagal part of the brain.
Dronabinol is already licensed to treat nausea and emesis caused by chemotherapy. Furthermore, cannabinoids have been shown to be effective in lowering nausea during the prolonged chemotherapy stage, which is poorly regulated by an antagonist receptor of 5-HT.
Stimulation of appetite:
Anorexia is among the most chronic conditions of advanced cancer patients, as it causes significant weight loss. THC and other cannabinoids have been shown in numerous studies to have a synergistic effect on hunger and boost food intake in animals at low-to-high doses.
Dronabinol is already licensed for the treatment of AIDS-related syndrome.
Psychological based effects:
Cannabinoids have been shown in vivo to have anti-anxiety properties at modest dosages. THC and nabilone have a favorable psychological effects, such as depression and anxiety reduction and improved sleep. These potentially beneficial effects could have an impact on the medical outcomes of terminally sick patients.
Effects of Antineoplastic:
In vitro studies on lung cancer, gliomas, skin cancer, lymphomas, breast cancer, prostate cancer, uterine cancer, neuroblastoma, and thyroid epithelioma revealed that THC, synthetic cannabinoid agonists, naturally occurring cannabinoids (CBD and cannabinol), and endocannabinoids have anti-cancer effects.
Natural and synthetic cannabis both have anti-cancer properties, according to in vivo studies.
Synthetic cannabinoids have anti-cancer effects in xenografts of lung cancer, thyroid cancer, skin cancer, epitheliomas, and gliomas, according to in vivo research.
Cannabinoid drug side effects
- The pharmaceutical cannabinoids, nabilone, and dronabinol, like many other medications, can also induce side effects and difficulties.
- Increased heart rate, low blood pressure (particularly when standing up), dizziness or lightheadedness, and fainting are symptoms that some people experience.
- These medicines might cause drowsiness, as well as mood swings or a “high”, feeling that some individuals find undesired.
- Because older individuals are more likely to experience side effects, they are frequently treated on lower doses.
- When taking cannabis medications, those who have suffered emotional problems, anxiety, or hallucinations may discover that their symptoms worsen.
Despite tremendous advancements in assessing cancer pain and therapies in recent years, there is still a significant percentage of patients with poorly controlled pain.
It would be ideal to have a comprehensive, holistic treatment strategy that included both pharmacological and pharmacogenetic-based precision therapy.
Several pieces of literature have documented the medical use of cannabis for the therapeutic management of a variety of ailments over time.