Medical cannabis refers to the use of the Cannabis plant as a physician-recommended herbal therapy as well as synthetic THC and cannabinoids. So far, the medical use of cannabis is legal only in a limited number of territories, including Canada, Belgium, Austria, the Netherlands, the United Kingdom, Spain, Israel, Finland, and some U.S. states. This usage generally requires a prescription, and distribution is usually done within a framework defined by local laws.
There are many studies regarding the use of cannabis in a medicinal context.
Cannabis, called dà má (大麻) in Chinese, is known to have been used in Taiwan for fiber starting about 10,000 years ago. Cannabis has been used for medicinal purposes for approximately 4,000 years. In the early 3rd century AD, Hua Tuo was the first in China to use cannabis as an anesthetic, which he reduced to powder and mixed with wine. Cannabis was prescribed to treat vomiting, and infectious and parasitic hemorrhaging.
Cannabis as a medicine became common throughout much of the world by the 19th century. It was used as the primary pain reliever until the invention of aspirin. Modern medical and scientific inquiry began with doctors like O'Shaughnessy and Moreau de Tours, who used it to treat melancholia and migraines, and as a sleeping aid, analgesic and anticonvulsant.
By the time the United States banned cannabis in a federal law, the 1937 Marijuana Tax Act, the plant was no longer extremely popular. Skepticism about marijuana arose in response to the bill. The situation was exacerbated by the stereotypes promoted by the media, that the drug was used primarily by Mexican and African immigrants.
Later in the century, researchers investigating methods of detecting cannabis intoxication discovered that smoking the drug reduced intraocular pressure.
In 1972 Tod H. Mikuriya, M.D. reignited the debate concerning marijuana as medicine when he published "Marijuana Medical Papers." High intraocular pressure causes blindness in glaucoma patients, so many believed that using the drug could prevent blindness in patients. Many Vietnam War veterans also believed that the drug prevented muscle spasms caused by battle-induced spinal injuries. Later medical use has focused primarily on its role in preventing the wasting syndromes and chronic loss of appetite associated with chemotherapy and AIDS, along with a variety of rare muscular and skeletal disorders. Less commonly, cannabis has been used in the treatment of alcoholism and addiction to other drugs such as heroin and the prevention of migraines. In recent years, studies have shown or researchers have speculated that the main chemical in the drug, THC, might help prevent atherosclerosis.
Later, in the 1970s, a synthetic version of THC, the primary active ingredient in cannabis, was synthesized to make the drug Marinol. Users reported several problems with Marinol, however, that led many to abandon the pill and resume smoking the plant. Patients complained that the violent nausea associated with chemotherapy made swallowing pills difficult. The effects of smoked cannabis are felt almost immediately, and is therefore easily dosed. Marinol (Jojel), like ingested cannabis, is very psychoactive, and is harder to titrate than smoked cannabis. Marinol has also consistently been more expensive than herbal cannabis. Some studies have indicated that other chemicals in the plant may have a synergistic effect with THC.
In addition, during the 1970s and 1980s, six U.S. states' health departments performed studies on the use of medical marijuana. These are widely considered some of the most useful and pioneering studies on the subject. Voters in eight states showed their support for marijuana prescriptions or recommendations given by physicians between 1996 and 1999, including Alaska, Arizona, California, Colorado, Maine, Nevada, Oregon, and Washington, going against policies of the federal government.
In May 2001, "The Chronic Cannabis Use in the Compassionate Investigational New Drug Program: An Examination of Benefits and Adverse Effects of Legal Clinical Cannabis" (Russo, Mathre, Byrne et al) was completed. This three-day examination of major body functions of four of the five living US federal cannabis patients found "mild pulmonary changes" in two patients.
On October 7, 2003, a patent (#6,630,507) entitled: "Cannabinoids as Antioxidants and Neuroprotectants" was awarded to the United States Department of Health and Human Services, based on research done at the National Institute of Mental Health (NIMH), and the National Institute of Neurological Disorders and Stroke (NINDS). This patent claims that cannabinoids are "useful in the treatment and prophylaxis of wide variety of oxidation associated diseases, such as ischemic, age-related, inflammatory and autoimmune diseases. The cannabinoids are found to have particular application as neuroprotectants, for example in limiting neurological damage following ischemic insults, such as stroke and trauma, or in the treatment of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease and HIV dementia."
Historian Jacob Appel has argued that the medicinal marijuana movement bears striking similarities to the medicinal beer movement of the 1920s. Both efforts attempted to muster medical expertise in the face of a national Prohibition and both pitted the rights of physicians against the authority of the federal government.
Cannabidiol, also known as "CBD", is a major constituent of medical cannabis. CBD represents up to 40% of extracts of the medical cannabis plant. Cannabidiol relieves convulsion, inflammation, anxiety, nausea, and inhibits cancer cell growth. Recent studies have shown cannabidiol to be as effective as atypical antipsychotics in treating schizophrenia. In November 2007 it was reported that CBD reduces growth of aggressive human breast cancer cells in vitro and reduces their invasiveness. It thus represents the first non-toxic exogenous agent that can lead to down-regulation of tumor aggressiveness. It is also a neuroprotective antioxidant.
Part of the mechanism by which medical cannabis has been shown to reduce tissue inflammation is via a compound called β-caryophyllene. A cannabinoid receptor called CB2 plays a vital part in reducing inflammation in humans and other animals. β-Caryophyllene has been shown to be a selective activator of the CB2 receptor. β-Caryophyllene is especially concentrated in cannabis essential oil, which contains about 12–35%.
In a year 2002 review of medical literature, medical cannabis was shown to have established effects in the treatment of nausea, vomiting, unintentional weight loss, and lack of appetite. Other "relatively well-confirmed" effects were in the treatment of "spasticity, painful conditions, especially neurogenic pain, movement disorders, asthma, [and] glaucoma." Elsewhere it has been shown to be beneficial in treating symptoms associated with treatments for cancer, AIDS, and hepatitis.
Cannabis also acts as an antispasmodic and anticonvulsant and is indicated for neurological conditions such as epilepsy especially complex partial seizures, multiple sclerosis, and spasms. As an analgesic and an immunomodulator it is indicated for conditions such as migraine, arthritis, spinal and skeletal disorders. As a bronchodilator it is beneficial for asthma. It also reduces the intraocular pressure and is indicated for glaucoma. Recent studies have shown the drug to be efficacious in treating mood disorders and mental health issues such as depression, post traumatic stress disorder, clinical depression, attention-deficit disorder, attention-deficit hyperactivity disorder, obsessive-compulsive disorder, panic disorder, Crohn's Disease and bipolar disorder.
It is also indicated for premenstrual syndrome, hypertension, and insomnia. It is also reported to be an effective treatment for constipation.
According to a survey on the recommendation of cannabis in California, cannabis is indicated for over 250 conditions.
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An increasing number of medical organizations have endorsed allowing patients access to medical marijuana with their physicians' approval. These include, but are not limited to, the following:
These medications are usually used when first line treatments for nausea fail to work. In extremely high doses and in rare cases there is a possibility of "psychotomimetic" side effects. The other commonly-used antiemetic drugs are not associated with these side effects.
The prescription drug Sativex, an extract of cannabis administered as a sublingual spray, has been approved in Canada for the adjunctive treatment (use along side other medicines) of both multiple sclerosis and cancer related pain. This medication may now be legally imported into the United Kingdom and Spain on prescription. Dr. William Notcutt is one of the chief researchers that has developed Sativex, and he has been working with GW and founder Geoffrey Guy since the company's inception in 1998. Notcutt states that the use of MS as the disease to study "had everything to do with politics."
| Medication | Year approved | Licensed indications | Cost |
|---|---|---|---|
| Nabilone | 1985 | Nausea of cancer chemotherapy that has failed to respond adequately to other antiemetics | $4000.00 U.S. for a year's supply (in Canada) |
| Marinol | 1992 | Nausea of cancer chemotherapy that has failed to respond adequately to other antiemetics, AIDS wasting | $723.16 U.S. for 30 doses @ 10 mg online |
| Sativex | 1995, 1997 | The product is approved in Canada as adjunctive treatment for the symptomatic relief of neuropathic pain in multiple sclerosis, and more recently for pain due to cancer. | $9,351 Canadian per year |
A major criticism of cannabis as medicine is opposition to smoking as a method of consumption. In contrast, the use of a vaporizer for cannabis administration delivers the active ingredients and their benefits very rapidly, without the health costs associated with smoking.
On 20 April, 2006, The United States Food and Drug Administration (FDA) issued an advisory against smoked medical marijuana stating that, "marijuana has a high potential for abuse, has no currently accepted medical use in treatment in the United States, and has a lack of accepted safety for use under medical supervision. Furthermore, there is currently sound evidence that smoked marijuana is harmful."
Some prominent American societies have been reluctant to endorse medicinal cannabis.
For example:
, the National Multiple Sclerosis Society
, the American Academy of Ophthalmology
and the American Cancer Society
(Federal Register, 1992).
The Institute of Medicine, run by the United States National Academy of Sciences, conducted a comprehensive study in 1999 to assess the potential health benefits of cannabis and its constituent cannabinoids. The study concluded that smoking cannabis is not recommended for the treatment of any disease condition, but did conclude that nausea, appetite loss, pain and anxiety can all be mitigated by marijuana. While the study expressed reservations about smoked marijuana due to the health risks associated with smoking, the study team concluded that until another mode of ingestion was perfected that could provide the same relief as smoked marijuana, there was no alternative. In addition, the study pointed out the inherent difficulty in marketing a non patentable herb. Pharmaceutical companies will not substantially profit unless there is a patent. For those reasons, the Institute of Medicine concluded that there is little future in smoked cannabis as a medically approved medication. The report also concluded for certain patients, such as the terminally ill or those with debilitating symptoms, the long-term risks are not of great concern.
In an unpublished 2001 study by the Mayo Clinic, Marinol was shown to be less effective than the steroid megestrol acetate in helping cancer patients regain lost appetites. The mechanism by which megestrol acetate works is unknown and the compound can cause "impotence, gas, rash, high blood pressure, fever, decreased libido, insomnia, upset stomach, and high blood sugar. . .," as well as "breakthrough bleeding" in women.
Many medical cannabis opponents note that smoking cannabis is harmful to the respiratory system. However, this harm can be minimalized or eliminated by the use of a vaporizer or ingesting the drug in an edible form or other non-smoking modes of delivery like tinctures. Vaporizers are devices that vaporize the active constituents (cannabinoids) and the fragrant aromatic substances in the preparation without combusting the plant material and thus preventing the formation of toxic substances. Studies have shown that vaporizers can dramatically reduce or even eliminate the release of irritants and toxic compounds.
In order to kill microorganisms, especially mold, the scientists "Levitz and Diamond (1991) suggested baking marijuana in home ovens at 150 °C [302 °F], for five minutes before smoking. Oven treatment killed conidia of A. fumigatus, A. flavus and A. niger, and did not degrade the active component of marijuana, tetrahydrocannabinol (THC)."
The cannabis distributed by Health Canada is provided under the brand CanniMed by the company Prairie Plant Systems Inc. That the demand from Canadian authorities would have increased by 80% in 2006 (the output reaching 420 kg the previous year). However, it is legal for patients approved by Health Canada to grow their own cannabis for personal consumption, and it is possible to obtain a production license as a person designated by a patient. Health Canada noted however that "no notice of compliance has been issued for marijuana for medical purposes."
Several studies have been conducted to study the effects of cannabis on patients suffering from disease like cancer, AIDS, multiple sclerosis, the seizures or the asthma. This research was conducted by various Spanish agencies at the Universidad Complutense de Madrid headed by Dr. Manuel Guzman, the hospital of La Laguna in Tenerife led neurosurgeon Luis González Feria or the University of Barcelona.
After legislation, several cannabis clubs have been established including the Basque Country and Catalonia. These clubs, the first of its kind in Europe, are non-profit associations who grow cannabis and sell it at cost to its members. In 2006, members of these clubs were acquitted in trial for possession and sale of cannabis.
In the United States, it is important to differentiate between medical cannabis at the federal and at the state level. At the federal level, cannabis per se has been made criminal by implementation of the Controlled Substances Act. States that have made medical marijuana legal at the state level, only allow it in marijuana form. Other forms of cannabis such as hashish, hash oil, etc. are still highly penalized.
The Federal Food, Drug, and Cosmetic Act makes the Food and Drug Administration (FDA) the sole government entity responsible for ensuring the safety and efficacy of new prescription and over-the-counter drugs, overseeing the labeling and marketing of drugs, and regulating the manufacturing and packaging of drugs. The FDA defines a drug as safe and effective for a specific indication if the clinical benefits to the patient are felt to outweigh any health risks the drug might pose. The FDA and comparable authorities in Western Europe including the Netherlands, have not approved smoked marijuana (some because of the problems related to smoking per se) for any condition or disease. Cannabis remains illegal throughout the United States and is not approved for prescription as medicine, although 12 states - Alaska, California, Colorado, Hawaii, Maine, Montana, Nevada, New Mexico, Oregon, Rhode Island, Vermont and Washington - approve and regulate its medical use. The federal government continues to enforce its prohibition in these states. However, there are also 2 states, Arizona and Maryland, whose drug laws are favourable towards the medicinal use of marijuana, in the latter case making it a non-incarcerable offense with a maximum penalty of a $100 fine,
but which still explicitly ban it.
Potential health benefits aside, marijuana remains a US federally controlled substance, making possession and distribution illegal. It has been estimated that an average marijuana clinic distributes a pound of cannabis per day, making acquisition a critical challenge. This acquisition may have to resort to more traditionally crime-associated, black-market sources, contributing to crime in communities. This point was illustrated in early 2007, with the murder of Denver, Colorado area medical cannabis activist Ken Gorman.
Researchers face similar challenges in obtaining medical cannabis for research trial. Recently, the US FDA has approved a number of cannabis research clinical trials, but the Drug Enforcement Agency has not granted licenses to the researchers in these studies.
Cannabis was listed in the United States Pharmacopeia from 1850 until 1942. The United States federal government does not currently recognize any legitimate medical use, although there are currently seven patients receiving cannabis for their various illnesses through the Compassionate Investigational New Drug program that was closed to new patients in 1991 by the George H. W. Bush administration. Francis L. Young, an administrative law judge with the United States Drug Enforcement Agency, in 1988, declared that "in its natural form, [cannabis] is one of the safest therapeutically active substances known. However, smoked cannabis is today not approved by the United States Food and Drug Administration (FDA). Twelve U.S. state laws currently allow for the medicinal use of cannabis, but the United States Supreme Court ruled that the federal government has the right to regulate and criminalize marijuana also in these states, even for medical purposes.
The term medical marijuana post-dates the U.S. Marijuana Tax Act of 1937, enacted by the Franklin D. Roosevelt administration, the effect of which made cannabis prescriptions illegal in the United States.
Information about medical cannabis in the U.S. western state of California can be found here:
In 1996 California voted Proposition 215, also called the Compassionate Use Act, into law. CA Senate Bill 420 was passed in 2003 to clarify Proposition 215 by specifying statewide minimum limits on possession of marijuana and enact a Statewide Medical Marijuana ID Card Program (the G214 card). As of January 16, 2008, only 36 of 58 counties are issuing cards in the program, with 18,847 cards having been issued,
however, participation in the ID Card program is optional and the identification card is not required to claim the Act's protections.
On November 5, 1996 56% of voters approved Proposition 215. The law removes state-level criminal penalties on the use, possession and cultivation of marijuana by patients who possess a "written or oral recommendation" from their physician that he or she "would benefit from medical marijuana." Patients diagnosed with any illness where the medical use of marijuana has been "deemed appropriate and has been recommended by a physician" are provided with legal protection under this act. Conditions typically covered by the law include: arthritis; cachexia; cancer; chronic pain; HIV or AIDS; epilepsy; migraine; and multiple sclerosis. No regulations regarding the amount of marijuana patients may possess and/or cultivate were provided by this act, though the California Legislature adopted guidelines in 2003.
On November 7, 2000, 54% of Colorado voters passed Amendment 20, which amends the Colorado State constitution to allow the medical use of marijuana. Patients can possess not more than 2 oz. (almost 57 g) of "usable marijuana" and not more than 6 marijuana plants, but they may neither take their medicine in public, nor even on their own property, if the public can see them taking it.
More information on medical marijuana in Montana is available here:
The Oregon medical cannabis program has the name, "The Oregon Medical Marijuana Program," which administers the Medical Marijuana Act approved there by the public in November of 1998. The Oregon Medical Marijuana Program administers the program within the Oregon Department of Human Services. As of April 1, 2008, there were 16,635 patients registered. Virtually all patients benefiting from the program suffer from severe pain and almost 2500 from nausea. The other conditions are given as epilepsy, AIDS / HIV, cancer, cachexia, chronic glaucoma and tremors caused by Alzheimer's disease.
More information is available at: Rhode Island Patient Advocacy Coalition and
, a patient prescribed medical marijuana may only keep a 60 day supply of it.
More information about medical marijuana in Vermont is available here:
Cannabis is in Schedule IV of the Single Convention on Narcotic Drugs, making it subject to special restrictions. Article 2 provides for the following, in reference to Schedule IV drugs:
This provision, while apparently providing for the limitation of cannabis to research purposes only, also seems to allow some latitude for nations to make their own judgments. The official Commentary on the Single Convention indicates that Parties are expected to make that judgment in good faith.
and Advisor on DHS/OMMP advisory committee on medical marijuana.