Medical Marijuana Image

1.    What is the history of its use?

There is recorded evidence of marijuana (cannabis) use for medicinal purposes in ancient cultures as far back as 2900 BC including: China, Egypt, India, Greece, and the medieval Islamic world. In these cultures, marijuana was used for medical conditions ranging from constipation and gastrointestinal disorders to gout, rheumatism, and pain relief.

In the modern era, marijuana was used in Western medicine for the treatment of ailments such as muscle spasms, gastrointestinal complaints, and pain relief.

Since the early 20th century, however, the use of marijuana has been illegal in most of the world.

 

2.    Where is the use of medicinal marijuana legal?

The use of marijuana for recreational purposes remains illegal in most countries. However, medicinal marijuana is legal in Canada, Austria, Finland, Germany, the Netherlands, Italy, Portugal, Spain and Israel.  According to federal law, marijuana remains illegal in the United States, although there are some states that have decriminalized marijuana for recreational and/or medicinal use.

 

3.    What are the medicinal components of marijuana?

Marijuana is a plant that is prepared and used either as a psychoactive drug, or as a medicine. There are 483 known compounds in the marijuana plant, including 84 cannabinoids, such as tetrahydrocannabinol (THC), and cannabidiol (CBD). THC is the cannabinoid with the greatest psychoactive effect, and mostly responsible for the high.

 

4.    What are its current medicinal uses?

Marijuana is currently used medicinally for the treatment of:

–      Nausea & vomiting induced by chemotherapy treatments

–      Anorexia associated with HIV/AIDS

–      Chronic pain caused by neuropathy, fibromyalgia, osteoarthritis and rheumatoid arthritis

–      Spasticity associated with multiple sclerosis

 

5.    What is the scientific evidence of benefits?

Strong scientific evidence for the medicinal use of marijuana is lacking, due mostly to the strict regulations of the drug, which inhibits extensive research. Some laboratory experiments have suggested that marijuana can have anti-cancer effects. In addition, there is some evidence for the beneficial effects of marijuana in Alzheimer’s disease, type 1 diabetes, and epilepsy; it may also have some therapeutic potential for treating bipolar disorder. Scientific studies have not seen strong evidence of benefit in treating Parkinson’s disease, Huntington’s disease, or glaucoma.

 

6.    What are the known risks and side effects?

Long-term use of marijuana can have adverse effects on cognitive function, especially in children and young-adults. In addition to the toxicities associated with the smoking of marijuana, there are risks of dependency on the drug. Moreover, marijuana use has been associated with an increase in mental health issues including: psychosis and depression and an increased risk of suicide.

Although less studied, other adverse effects may include an increased risk of various cancers and negative effects on reproductive health, however, more study is needed to further clarify and confirm these risks.

 

7.    What is the pro side of the debate?

Those in favor of medicinal marijuana argue that it is a safe and effective treatment for many medical conditions. There are those who believe in its advantages, or claim to have experienced its benefits with less side effects than other medications they have tried.

This side of the debate states that there are no reported cases of lung cancer or emphysema as a result of smoking marijuana, while the widely available tobacco cigarettes are harmful and highly addictive.

While there are some pharmaceutical products derived from, or containing synthetic components of marijuana, they contain only one or two of the 84 potentially beneficial cannabinoids contained in the whole plant. For this reason, proponents of medical marijuana state that the legally available pharmaceuticals are not as effective as the entire plant.

Another point made by those on this side of the debate is that there is not as much evidence to support addiction to marijuana as is seen for tobacco, alcohol, or other drugs. Moreover, they dispute the argument that marijuana will lead to the use of ‘harder drugs’, because this has not been scientifically proven. Instead, it is suggested that marijuana is more likely a ‘starter drug’ due to the relative ease of obtaining it compared to harder drugs.

 

8.    What is the con side of the debate?

Those who are opposed to the use of medical marijuana say that there is little scientific evidence to support the use of marijuana for medicinal purposes, while there are toxic side-effects and other health concerns associated with its use. This is particularly concerning for children, as there is evidence that the use of marijuana can increase the likelihood of long-term cognitive problems, as well as psychiatric disorders.

The general consensus amongst opponents of medical marijuana is that it is a dangerous ‘gateway drug’ that can lead to the use of drugs that are much more dangerous and addictive. There is evidence that marijuana is also addictive, with withdrawal symptoms reported such as decreased appetite, difficulty sleeping, weight loss, and irritability. They argue that there are many other legal pharmaceuticals available that are effective and have fewer side effects or related problems as marijuana.

This side of the debate may doubt the medicinal benefit of marijuana altogether, or may be proponents of safety. The marijuana plant contains over 400 chemicals and 84 cannabinoids. These chemicals are present in differing concentrations depending on how the plant has been grown and prepared, leading to difficulty in controlling or regulating the safety and dosages of crude marijuana. For this reason, pharmaceutical preparations of marijuana extracts or synthetic cannabinoids are a regulated and safer alternative that is available in stable doses.

 

9.    What are the current marijuana-based pharmacological agents available to patients?

Currently Available:

Marinol (Dronabinol) – a synthetic version of delta-9-THC has been available in the United States since 1985. It is currently used to treat nausea and vomiting associated with chemotherapy. Marinol is also used to treat anorexia associated with AIDS.

Sativex (Nabiximols) – the first cannabis-based medicine, on the market in the UK in 2010. Sativex is a mouth spray that is derived from natural extracts of the marijuana plant, containing both THC and CBD. It is currently used to treat spasticity and neuropathic pain associated with multiple sclerosis. It is also in development for use to treat chronic pain associated with advanced cancer and neuropathic pain from various medical conditions.

Cesamet (Nabilone) – a synthetic cannabinoid that mimics THC. It is currently used to treat nausea and vomiting associated with chemotherapy. It is also used off label for the treatment of chronic pain conditions.

Currently Under Investigation:

Epidiolex – a cannabinoid purified from the marijuana plant, containing no THC. Epidiolex is not currently approved by the FDA or any other national regulatory agency. It is currently being investigated as a treatment for children with epilepsy.

Namisol – an oral tablet containing pure, natural delta-9-THC. Namisol is currently being investigated for the treatment of patients with multiple sclerosis, Alzheimer’s and chronic pain.

 

10. What clinical trials are currently underway using marijuana?

There are many clinical trials currently recruiting using marijuana or marijuana-based medicines for various medical conditions, including:

–      Pain associated with advanced cancer

–      Chronic pain associated with sickle cell anemia

–      Spasticity for multiple sclerosis

–      Spinal cord injury and pain

–      Motor neuron disease

–      Anorexia associated with HIV

–      Parkinson’s disease tremor

–      Spasticity in children aged 8-18 years

–      Dementia

–      Crohn’s disease

–      Abdominal pain associated with chronic pancreatitis

In addition to these studies assessing the medicinal benefits of marijuana, there are also current studies that are designed to further investigate the effects of marijuana in humans, including effects on brain morphology and cognitive impairment.

 

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Epidiolex fact sheet. Available from: http://www.gwpharm.com/Epidiolex.aspx Last Accessed: March 19, 2014.

Namisol fact sheet. Available from: http://www.echo-pharma.com/en/products-and-pipeline/namisol/ Last Accessed: March 19, 2014.

Clinical trials.gov “Evaluation Prospectively the Level of Reduction in Cognitive Functions of Cancer Patients Who Are on Active Oncology Treatments and Use Cannabis. The Second Goal is to Identify High-risk Groups for Cognitive Impairment Due to Cannabis Use.” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01983267?term=cannabis&rank=2 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Vaporized Cannabis for Chronic Pain Associated With Sickle Cell Disease (Cannabis-SCD)” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01771731?term=cannabis&rank=10 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Cannabis for Spasticity in Multiple Sclerosis” Available from: http://www.clinicaltrials.gov/ct2/show/NCT00682929?term=cannabis&rank=17 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Vaporized Cannabis and Spinal Cord Injury Pain” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01555983?term=cannabis&rank=24 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Safety and Efficacy on Spasticity Symptoms of a Cannabis Sativa Extract in Motor Neuron Disease (CANALS)” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01776970?term=cannabis&rank=44 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Effectiveness of Cannabis in the Treatment of Tinnitus Patients” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01969474?term=cannabis&rank=53 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Long Term Safety of Sativex® Oromucosal Spray (Sativex®; Nabiximols) as Adjunctive Therapy in Patients With Uncontrolled Persistent Chronic Cancer Related Pain” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01337089?term=cannabis&rank=66 Last Accessed: March 19, 2014.

Clinicaltrials.gov “A Study of the Safety and Effectiveness of Nabiximols (Sativex), for the Relief of Symptoms of Spasticity in Subjects, From Part B, With Multiple Sclerosis.” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01868048?term=cannabis&rank=74 Last Accessed: March 19, 2014.

Clinicaltrials.gov “A Two-Part Study of Sativex® Oromucosal Spray for Relieving Uncontrolled Persistent Pain in Patients With Advanced Cancer” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01424566?term=cannabis&rank=92 Last Accessed: March 19, 2014.

Clinicaltrials.gov “A Safety Study of Sativex in Combination With Dose-intense Temozolomide in Patients With Recurrent Glioblastoma” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01812603?term=cannabis&rank=97 Last Accessed:
March 19, 2014.

Clinicaltrials.gov “Sativex® for Relieving Persistent Pain in Patients With Advanced Cancer (SPRAY III)” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01361607?term=cannabis&rank=100 Last Accessed: March 19, 2014.

Clinicaltrials.gov “A Safety Study of Sativex Compared With Placebo (Both With Dose-intense Temozolomide) in Recurrent Glioblastoma Patients” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01812616?term=cannabis&rank=121 Last Accessed: March 19, 2014.

Clinicaltrials.gov “A Study of Sativex® for Relieving Persistent Pain in Patients With Advanced Cancer” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01262651?term=cannabis&rank=140 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Medical Marijuana Use in HIV+ Patients Prospective Cohort Study (MMC-1)” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01536899?term=cannabis&rank=146 Last Accessed: March 19, 2014.

Clinicaltrials.gov “A Safety, Efficacy and Tolerability Study of Sativex for the Treatment of Spasticity in Children Aged 8 to 18 Years” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01898520?term=cannabis&rank=149 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Cannabis and Parkinson’s Disease Tremor: A Natural History Study” Available from: http://www.clinicaltrials.gov/ct2/show/NCT02028858?term=cannabis&rank=200 Last Accessed: March 19, 2014.

Clinicaltrials.gov “The Effects of Cannabidiol and ∆-9-THC in Humans” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01180374?term=cannabis&rank=224 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Delta-THC in Dementia” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01608217?term=cannabis&rank=228 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Combined THC and CBD Drops for Treatment of Crohn’s Disease” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01826188?term=cannabis&rank=253 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Δ9-THC (Namisol®) in Chronic Pancreatitis Patients Suffering From Persistent Abdominal Pain” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01551511?term=cannabis&rank=275 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Cannabinoid Modulation of Pain” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01595620?term=cannabis&rank=289 Last Accessed: March 19, 2014.

Clinicaltrials.gov “Cannabis Effects on Brain Morphology in Aging (CAN)” Available from: http://www.clinicaltrials.gov/ct2/show/NCT01874886?term=cannabis&recr=Open&no_unk=Y&rank=35 Last Accessed: March 19, 2014.

Image courtesy of Paul / FreeDigitalPhotos.net

 

Written by Deborah Tallarigo, PhD

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