The Medical Uses of Cannabis

The Medical Uses of Cannabis

Cannabis (Cannabis sativa) has a long and storied history as a medicinal plant, with its use dating back more than two millennia. Ancient civilizations, including the Chinese, Indians, and Egyptians, recognized the therapeutic potential of cannabis and incorporated it into their medical practices. Chinese Emperor Shen Nung is said to have used cannabis for its healing properties as early as 2737 BCE. In ancient India, cannabis was used in traditional Ayurvedic medicine for its analgesic, anti-inflammatory, and anticonvulsant properties. Egyptian medical texts from around 1550 BCE mention cannabis as a treatment for inflammation.

By the 19th century, cannabis had become a staple in Western medicine, widely used to treat various ailments, from pain and inflammation to epilepsy and insomnia. The American pharmacopeia included cannabis tinctures until the early 20th century, when regulatory changes led to its removal. The rediscovery and resurgence of interest in cannabis for medical use began in the late 20th century, spurred by the movement to legalize it for therapeutic purposes in several US states. Today, medical cannabis is legal in many parts of the world, and its potential to alleviate symptoms of numerous conditions is being rigorously explored.

This article explores the various medical uses of cannabis, methods of administration, and the research underpinning its effectiveness for different ailments.

Methods of Administration

Cannabis can be administered in several ways, each offering unique benefits and challenges:

1. Inhalation: Smoking or vaporizing cannabis delivers cannabinoids directly to the bloodstream through the lungs, providing rapid relief. Vape pens are a cheap and easy method that is often used for conditions requiring immediate symptom alleviation, such as chronic pain or nausea.
2. Oral Ingestion: Cannabis can be consumed in edibles, tinctures, or capsules. This method has a delayed onset of effects but provides longer-lasting relief, making it suitable for chronic conditions.
3. Topical Application: Cannabis-infused creams, balms, and oils are applied directly to the skin, offering localized relief without psychoactive effects. This is beneficial for treating localized pain and inflammation.
4. Sublingual Administration: Tinctures or oils placed under the tongue are absorbed quickly into the bloodstream, providing a balance between the rapid onset of inhalation and the long-lasting effects of oral ingestion.

Medical Conditions Treated with Cannabis

Chronic Pain

Relief from chronic pain is the most common reason patients seek medical cannabis. Studies show high percentages of patients using cannabis for severe pain, such as 94% of Colorado medical marijuana ID cardholders and 87% of participants in another study. Evidence suggests that some patients are replacing opioids with cannabis, with a Michigan study reporting a 64% reduction in opioid use among pain patients using medical cannabis. Analysis of Medicare Part D data indicates a significant reduction in opioid prescriptions in states with medical cannabis laws.

Research:

• A study in the Journal of Pain found that vaporized cannabis significantly reduced neuropathic pain in patients with peripheral neuropathy.
• The National Academies of Sciences, Engineering, and Medicine (NASEM) concluded there is substantial evidence supporting cannabis use for chronic pain in adults.

Cancer

Cannabis has shown potential in managing cancer symptoms and side effects of cancer treatments. Cannabinoids may play a role in cancer regulation.

Research:

• Nabilone and dronabinol were approved in 1985 for treating chemotherapy-induced nausea and vomiting in patients unresponsive to conventional treatments.

Chemotherapy-Induced Nausea and Vomiting

Nausea and vomiting are common side effects of chemotherapy. Cannabis-based medications like nabilone and dronabinol have been effective antiemetics.

Research:

• Studies indicate that cannabinoids can reduce chemotherapy-induced nausea and vomiting effectively, with fewer side effects compared to traditional antiemetics.

Anorexia and Weight Loss

Anorexia and weight loss are side effects of various diseases, notably cancer and AIDS. Dronabinol was approved in 1992 to treat anorexia associated with weight loss in AIDS patients.

Research:

• Systematic reviews of trials involving cannabinoid therapies for HIV/AIDS patients suggest some evidence of effectiveness in weight gain. Studies reported increased weight and appetite in patients using cannabis or dronabinol compared to placebo.
• A Phase III trial found no significant difference in appetite or weight gain between cannabis extract, THC, and placebo in cancer-related anorexia-cachexia syndrome patients.

Multiple Sclerosis (MS)

MS patients often suffer from spasticity, pain, and bladder dysfunction. Cannabis has shown promise in alleviating these symptoms.

Research:

• Studies found that cannabis extracts significantly reduced spasticity and pain in MS patients.
• Sativex, an oromucosal spray containing THC and CBD, improved muscle stiffness and spasm frequency.

Epilepsy

CBD has garnered attention for its anticonvulsant properties, particularly in treatment-resistant forms of epilepsy such as Dravet syndrome and Lennox-Gastaut syndrome.

Research:

• A study in the New England Journal of Medicine showed that CBD significantly reduced seizure frequency in Dravet syndrome patients.
• The FDA-approved Epidiolex, a CBD-based medication for treating severe epilepsy, underscoring the clinical recognition of cannabis's benefits in this area.

Anxiety and PTSD

Cannabis, particularly CBD, is increasingly used to manage anxiety and PTSD symptoms. CBD's anxiolytic properties are attributed to its interaction with serotonin receptors.

Research:

• A study in the Permanente Journal found that CBD reduced anxiety scores in 79% of participants within the first month of use.
• Research in the Journal of Affective Disorders indicated that cannabis use significantly reduced PTSD-related symptoms such as insomnia and hyperarousal.

Inflammatory Bowel Disease (IBD)

Cannabis has shown potential in alleviating symptoms of IBD, including Crohn's disease and ulcerative colitis, by reducing inflammation and pain.

Research:

• A study in Clinical Gastroenterology and Hepatology reported that cannabis use led to clinical improvement in Crohn's disease patients, although remission was not achieved.
• Another study found that cannabis improved the quality of life and reduced the need for other medications in ulcerative colitis patients.

Glaucoma

Cannabis can lower intraocular pressure (IOP), offering a potential treatment for glaucoma, a leading cause of blindness.

Research:

• Studies in the 1970s and 1980s demonstrated that smoking cannabis reduced IOP in glaucoma patients. However, the effects were short-lived, necessitating frequent dosing.

Historical and Regulatory Context

Cannabis was available as a licensed medicine in the US for about a century before being removed from the US Pharmacopeia in 1942. In 1985, THC preparations—dronabinol and nabilone—were approved for therapeutic use, reintroducing cannabinoids into medical practice. Recently, trials have focused on CBD for conditions like epilepsy and schizophrenia, although no CBD preparations have come to market yet. Nabiximols, an oromucosal spray with THC and CBD, is undergoing Phase III clinical trials in the US.

Legislative Landscape

The movement to make cannabis available as a medicine began in 1996 when Arizona and California first passed medicinal cannabis legislation. By 2016, 28 states and the District of Columbia had legalized medical cannabis; eight states had legalized both medical and recreational use, and another 16 states had allowed limited access to low-THC/high-CBD products (NCSL, 2016). Surveys show that among current adult users, 10.5% use cannabis solely for medical purposes, and 46.6% use it for both medical and recreational purposes (Schauer et al., 2016).

Common Conditions Treated with Cannabis

In states where medical cannabis is legal, it is commonly used for conditions such as anorexia and weight loss associated with HIV, chronic pain, amyotrophic lateral sclerosis, cancer, chemotherapy-induced nausea and vomiting, dementia, dystonia, epilepsy, glaucoma, Huntington's disease, irritable bowel syndrome, Parkinson's disease, spasticity, Tourette syndrome, traumatic brain injury, addiction, anxiety, depression, sleep disorders, post-traumatic stress disorder, and schizophrenia and other psychoses.

Conclusion

The medical use of cannabis is supported by a growing body of research highlighting its potential to treat a variety of conditions. While more large-scale clinical trials are needed to understand its benefits and risks fully, current evidence indicates that cannabis can be an effective and versatile treatment option. Its varied methods of administration allow for tailored therapeutic approaches, enhancing its potential in modern medicine. As research continues, cannabis may play an increasingly prominent role in the management of numerous medical conditions.