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Frequently Asked Questions on Medical Cannabis

Nandor Tanczos MP

04 Jul 2003
Subjects: Drug Law Reform, Health

Spokesperson: 
Green Party


How long has cannabis been used for medicinal purposes?

There is evidence that cannabis has been used for over 12,000 years; there are texts from as far back as 2737B.C. which list the medicinal uses of cannabis (1), (2), (4), (8).

Medicinal products were often labelled as hemp or Indian hemp, for example, Grimaults Indian Cigarettes for asthma, Frozol-ice corn pads, Chlorodyne for dysentery, diarrhoea, fever, spasms, colds, coughs and bronchitis and doctors often prescribed Indian hemp for tetanus, venereal disease, delirium, increasing appetite and other ailments (2).

The medical uses of cannabis have recently been rediscovered by researchers and health practitioners around the world, and many countries are recognising these medicinal benefits by enacting changes to their laws.
International Perspective:
Canada: legalized cannabis for medicinal use. Standardised cannabis strains are currently being grown and will be available on prescription by the end of this year. In the mean time, the Minister of Health has so far issued permits to patients allowing them to grow their own cannabis until the official prescription supply is ready.
United States: eight individual states (including Oregon, Hawaii and Alaska) have enacted legislation whereby patients who suffer from certain serious or debilitating medical conditions may be granted authorization to possess marihuana for personal medical use. Patients may also be permitted to grow marihuana for this purpose, since there would otherwise be no legitimate supply.
Australia: The medical use of marihuana is currently prohibited in all states and territories of Australia. However, the government of New South Wales (NSW) commissioned a report to advise the NSW government on whether to allow patients with certain medical conditions to use cannabis. The report recommended a "compassionate regime" whereby patients would be allowed to grow their own cannabis until the government can begin prescribing it.
Netherlands: In December 2000, the Ministry of Health, Welfare and Sport of the Netherlands announced its intention to establish an Office of Medicinal Cannabis. The goals of this office are to determine whether marihuana may be useful as a medicine. The office will also be the regulator for the production of cannabis for medical research purposes

UK: The UK Government has licensed GW Pharmaceuticals to breed cannabis strains to treat specific illnesses, and clinical trials have begun. The UK Police have stopped prosecuting patients using cannabis as medicine.

New Zealand: The New Zealand Misuse of Drugs Act 1975 imposes a ban on the use of cannabis. The Minister of Health has the power under section 14 of the MDA to issue licences permitting medicinal cannabis use. Although applications have been received by the Minister, none have been granted.

No one is claiming that cannabis is a "miracle" drug or cure, but it is becoming clear that cannabis can alleviate the suffering of many people with a variety of conditions.


What are the medical uses of cannabis?

THC and other cannabinoid's have been shown to have analgesic, anti-spasmodic, anti-convulsant, anti-tremor, anti-psychotic, anti-inflammatory, anti-emetic and appetite-stimulant properties. Research is ongoing into the Neuro protective and immunomodulatory effects of cannabinoid's (3),(6),(8).

Conditions which may benefit from medicinal cannabis:

  • multiple sclerosis,
  • spinal cord injury,
  • chronic pain,
  • some seizure disorders,
  • glaucoma,
  • asthma,
  • anxiety,
  • arthritis,
  • anorexia,
  • brain injury,
  • stroke,
  • migraines,
  • phantom limb pain,
  • Tourette's syndrome,
  • movement disorders,
  • depression, and
  • addiction withdrawal

(1),(2),(3),(6),(8).

Cannabis has also been shown to help alleviate the nausea and vomiting associated with cancer chemotherapy and cachexia in HIV/AIDS (2),(6),(8),(12),(13)


But won't people just try to get "high" on medical cannabis?

Patients who wish to use medicinal cannabis have a recognised, diagnosed condition which can be alleviated by cannabis.
The dosage required to obtain the medical benefits are lower than that required to become intoxicated (1),(6),(8).

Patients who are suffering emphasize that they seek medical relief, without intoxication, similar to patients who use self-administered morphine for pain control. They control the dose to relieve their pain while trying to minimise any side effects.

Cannabis, like many prescription drugs, can be abused and can be psychologically habituating, although cannabis is considerably less addictive and less harmful than many other prescribed drugs (1),(3),(5),(6),(7,)(8).

Decisions regarding the best medication for a patient are the responsibility of the health practitioner in conjunction with the patient themselves. If we were to deny the availability of a drug on the basis that it may be abused, we would have to remove a huge range of medications from use.


Can people overdose on cannabis?

Cannabis use encompasses 12,000 years of human experience and is now used daily by enormous numbers of people for recreation, yet there is no credible medical report to suggest that consuming marijuana has caused a single death (8), (17), (18).

Nearly all medicines have toxic, potentially lethal effects; however, researchers have been unable to identify the amount of cannabis which would need to be consumed in order to cause death (19).
Estimates indicate that a person would have to consume 20,000 to 40,000 times as much cannabis as is contained in one cannabis cigarette, and they would have to consume this amount in a short space of time (e.g. less than 1 hour) (8).

By contrast aspirin, a commonly used, over-the-counter medicine, causes hundreds of deaths each year (18).

In practical terms, marijuana cannot induce a lethal response as a result of drug-related toxicity (17), (18), (19)

But smoking cannabis can cause respiratory problems, are there other ways to take cannabis?
Smoking can cause irritation of the throat and lungs, and can lead to respiratory conditions such as bronchitis (20), (21), and can be particularly dangerous for people with compromised immune systems.
Smoking cannabis produces a hot smoke that can irritate delicate lung tissues and aggravate existing respiratory problems (14),(15)
Many patients prefer to use other methods of consumption such as vaporizers or take their cannabis orally or even topically using tinctures.

It should be noted that in the case of chronically ill people with a short life expectancy, possible lung damage from smoking cannabis is likely to be a small consideration in return for the benefits to be obtained from use.

The important aspects of medicinal use of cannabis are to achieve quick action and to effectively obtain dose control. This can be achieved in a variety of ways:

Tinctures:
Tinctures are not new. Until cannabis was banned in the 1930's, tinctures were the primary type of cannabis medicines. Tinctures are essentially alcohol extractions of whole cannabis, and are easy to make and very inexpensive. Many homeopathic preparations are also tinctures.
An important aspect of tinctures is that they contain all 60 of the essential cannabinoid's. Some of the cannabinoid's such as cannibidiol (CBD) actually reduce the psychoactive effects of THC while increasing the overall efficacy of the preparation.
The best way to use tinctures is sublingually (under the tongue). Titration or dose control is easily achieved by the number of drops a patient places under the tongue where the medicine is rapidly absorbed into the arterial system and is quickly transported to the brain and body. All a patient needs to do with tincture is use a few drops, wait for the desired medical effects, and either use more or stop as the situation indicates. Tinctures can be flavoured for better taste. Since tinctures average some 75% ethanol there is little worry of bacterial or other biological contamination. Those who wish to avoid alcohol can instead use their tincture as a base for making a concentrated elixir. While elixir is absorbed into the venous system via the gastrointestinal tract it is still reasonably quick acting if used on an empty stomach. Elixir is usually made with honey and tastes quite good. It can be used by the teaspoon either alone or in a beverage of choice like tea (15), (16).

Edibles: i.e. candies, glycerol drops, honey, chocolates etc.(24). Medicinal cannabis can be taken in a number of edible ways, easily prepared by the patient, which remove the health effects of smoking cannabis.

Vaporizers:
All vaporizers essentially use a controlled heating element that raises the temperature of whole cannabis samples just to the point where the cannabinoid's vaporize; this is a temperature lower than that required for burning.
There is no combustion with vaporization and no chemical conversion from heat. There is no hot smoke to irritate the lungs and no annoying combustion by-products.
Vaporizing is far more efficient in delivering medicine than smoking so in the long run using a vaporiser is cheaper than smoking as well as much healthier. Just as with smoking, a patient inhales a dose of vapour and waits one or two minutes to evaluate the effect. Patients can use only that amount that is necessary for the relief of symptoms. An added benefit of vaporizing is that there is little cannabis odour which can be important for both security reasons and general decorum. There are a wide variety of vaporizer systems that vary greatly in ease of use and cost (10), (11), (15)

Inhalers:
GW Pharmaceuticals has developed inhalers, sublingual (under the tongue) spays and tablets and an advanced dispensing system (an inhaler - like device which can monitor the usage to ensure excessive amounts are not used, therefore reducing the risk of abuse). (3).

Other strategies to reduce the risks of smoking medicinal cannabis are:

  • The use of cannabis strains with high THC content. Using higher THC content or high grade cannabis reduces the amount which will be required to obtain a medicinal dose. Sometimes cannabis is smoked together with tobacco or other dried herbs. This procedure should be avoided to minimize the inhalation of smoke from burnt plant material (15).
  • The use of pipes. Pipes are superior to cigarettes in some situations in that they easily allow the patient to smoke small amounts of pure high-grade cannabis. The percentage of tars in the smoke is reduced by condensation on the pipe walls. Pipes should be cleaned frequently. Water pipes are inferior to cigarettes and should be avoided (15).
  • The use of cannabis that is free of natural contaminants and adulterants. Only disease-free cannabis should be harvested and air-dried(15). Organically grown cannabis would be best.
  • Combination of oral use and inhalation. A regular (e.g. daily) oral dose combined with a demand inhaled medication. This is similar to some pain management regimes where (for example) a daily oral dose of morphine may be combined with an on-demand pethadine administration via I.V. (15).


But aren't there artificial cannabis products available?

The present pill (Marinol) has proven very unsatisfactory due to a long delay of action time, poor absorption in the gastrointestinal tract, and its failure to include many of the antioxidant and anti-inflammatory cannabinoid's present in whole cannabis and its extracts (there is evidence to suggest that the combination of all cannabinoid's together, such as is in whole plant material, produces a greater beneficial effect than the individual effects of each cannabinoid would suggest). Marinol has only one cannabinoid present.(7),(22),(23)

Some patients who have used Marinol report that it is not as effective as smoking cannabis, while others have reported that it caused uncontrollable "highs" (22),(23).

In addition, such pharmaceuticals are usually expensive and not subsidised by Pharmac.


What side effects are there from medicinal cannabis use?

All possible side effects are dose dependent. Therapy should start with low doses, slowly increasing, so that the individual dose can be determined and unwanted side effects can be avoided (8).

Many side effects are dose dependent and generally disappear within hours or 1-3 days without specific treatment

Frequent physical side effects are dry mouth, movement disorder, muscle weakness, slurred speech, increase of heart rate, decrease of blood pressure in vertical position, eventually with dizziness. In case of dizziness the affected should lay down. In horizontal position a slightly higher blood pressure may be measured (8),(19),(25).

Rare side effects are nausea and head aches (8).

Acute side effects are sedation, euphoria ("high"), dysphoria, fear of dying, feelings of loss of control, impairment of memory, altered time perception, depression, hallucinations (19),(25).
In case of strong side effects the person should be brought to a calm place and "talked down".
Side effects are dose dependent and generally disappear within hours or 1-3 days without specific treatment (8).

Side effects of long-term therapy

  • Development of tolerance is described for a multitude of effects, among them psychomotor impairment, effects on heart and circulation, effects on the hormonal system, intraocular pressure, and anti-emetic effects. Tolerance means that the effect decreases with time during use of cannabis. Tolerance may appear with repeated doses within weeks with different extent for different effects (8),(25).
  • Dependency and withdrawal have not been described in patients that were long-term treated with cannabis. But withdrawal has been observed in recreational users. Therefore withdrawal symptoms (anxiety, restlessness, insomnia, salivation, diarrhoea) may potentially occur (5), (8).
  • Psychosis. The course of a psychosis may be influenced unfavourably. In vulnerable persons the onset of a psychosis may be accelerated or triggered (8),(19).


Can you use cannabis with other medications?

Although medical marijuana is not officially approved, marijuana has been used around the world for treating a variety of medical disorders, such as nausea and vomiting associated with cancer chemotherapy, weight loss associated with AIDS (9), and spasticity from neurological diseases. In each instance, other drugs are also present. So far, no adverse interactions from such use have been reported (26)(27).

One of the most reasonable therapeutic uses of marijuana and THC has been to ameliorate the nausea and vomiting associated with cancer chemotherapy. In such cases, cannabis has been used simultaneously with many highly toxic cancer drugs with no reported adverse interactions (26)(27).

A somewhat similar situation applies to the therapeutic use of orally administered THC in treating the weight loss associated with AIDS (9), and treatment for spasticity associated with neurological disorders, such as multiple sclerosis and spinal cord injury, where THC may be added to therapies with muscle relaxants (26)(27).

References:

1) Alliance for Cannabis Therapeutics website; http://www.marijuana-as-medicine.org/Alliance/facts.html
2) Yska, Redmer; "New Zealand Green: the story of marijuana in New Zealand"; 1990, David Bateman Ltd.
3) GW Pharmaceuticals webpage.
4) "History of the Medical Use of Marijuana"; from the National Commission of Marijuana and Drug Abuse
5) "Marijuana and Medicine: Assessing the Science Base"; Janet E. Joy, Stanley J. Watson, Jr., and John A. Benson, Jr., Editors
Division of Neuroscience and Behavioral Health; INSTITUTE OF MEDICINE; NATIONAL ACADEMY PRESS; Washington, D.C. 1999
6) American Alliance for Medicinal Cannabis; http://www.letfreedomgrow.com/
7) "Medical Cannabis: The Patient's and the Doctor's Dilemmas"; by Lester Grinspoon, M.D.; *Editorial: Addiction Research, 2000, Vol. 8, No.1, pp. 1-4
8) International Association for Cannabis as a Medicine; http://www.acmed.org/
9) The Pharmacokinetic (PK) Effects of Marijuana (THC) on Nelfinavir (NFV) and Indinavir (IDV) (Poster 745)
Authored by B. Kosel, F. Aweeka, N. Benowitz, S. Shade, R. Leiser, A. Jayewardene, J. Stone, P. Lizak, and D. Abrams
10) "Study Shows Vaporizer Can Drastically Reduce Toxins in Marijuana Smoke"; California NORML/MAPS Press Release; May 2, 2003
11) "Vaporizer Research: An Update"; Dale Gieringer, Ph.D. (canorml@igc.apc.org); http://www.maps.org/
12) "Inhalation Marijuana as an Antiemetic for Cancer Chemotherapy" by Vincent Vinciguerra, MD; Terry Moore, MSW; Eileen Brennan, RNN13) "Oral vs. Inhaled Cannabinoids for Nausea/Vomiting from Cancer Chemotherapy"; New Mexico State Dept. of Health; 6 Nov 1988
14) Tashkin DP. Respiratory risks from marijuana smoking. Grotenhermen F, Russo E, eds. Cannabis and cannabinoids. Pharmacology, toxicology, and therapeutic potential. Binghamton NY: Haworth Press, 2001
15) Grotenhermen F. Harm reduction associated with inhalation and oral administration of cannabis and THC. Journal of Cannabis Therapeutics 2001
16) Gállego JT: Tintura de cannabis. Canamo, No 46, July 2001:76-77.
17) "Marijuana: The Forbidden Medicine"; Lester Grinspoon, MD, James B. Bakalar (Contributor); 1997; Yale University
18)"HOW DANGEROUS IS MARIJUANA COMPARED WITH OTHER SUBSTANCES?"; Jack Heher; http://www.jackherer.com/comparison.html
19)The Report of the National Commission on Marihuana and Drug Abuse: Acute Effects of Marihuana
20) "Cannabis Therapeutics in HIV/AIDS" ; Journal of Cannabis Therapeutics; Volume 1, Numbers 3/4
21) Airway Inflammation in Young Marijuana and Tobacco Smokers; Roth M.D. et al; American Journal of Respiratory and Critical Care Medicine; 1998
22) Synthetic THC / Marinol; Arkansas Alliance for Medical Marijuana; http://www.ardpark.org/reference/marinol.htm
23) "Marinol and Cannabis" ;Tod H. Mikuriya, M.D, Medical Co-ordinator; Americans for Compassionate Use; March 24, 1994
24) personal accounts of a medical cannabis patient: http://www.ryanrsd.net/MMJ.html
25) Information on Marinol (dronabinol, THC), Unimed Pharmaceuticals, Inc., January 2001, www.marinol.com (physicians information)
26) Grotenhermen F. Practical hints. In: Grotenhermen F, Russo E, eds. Cannabis and cannabinoids. Pharmacology, toxicology, and therapeutic potential. Haworth Press, Binghamton/New York 2001, in press
27) Hollister LE. Interactions of marihuana and D9-THC with other drugs. In: Nahas G, Sutin KM, Harvey DJ, Agurell S, eds. Marihuana and medicine. Totowa, NJ: Humana Press, 1999, pp. 273-277.