Chapter 9 - Use of marijuana for therapeutic purposes 

Marijuana as a drug?

In order for a product to be recognized as a drug in the pharmacopoeia, it must meet at least three criteria:

··               Quality: the dosage must be determined based on a constant and known composition that is easy to administer to the patient;

··               Effectiveness: rigorous clinical trials must have demonstrated the effectiveness of the drug; and

··               Safety: studies must show the known and foreseeable side effects of the drug.

 

Because of the lack of rigorous clinical studies using recognized protocols, whole marijuana has not yet met these criteria. There are a number of reasons for this. First, the research protocols needed to test drugs involve double-blind tests with control groups and randomly selected subjects, all conditions that are hard to achieve with marijuana. Second, the current legal climate limits the potential for such studies in terms of both the availability of marijuana and test conditions. Third, the marijuana provided by the National Institute of Drug Abuse (NIDA) for medical research – including research conducted by Health Canada – is of dubious quality:[1][20] THC concentration may be a determining factor in the quality of the therapeutic effects, yet NIDA marijuana contains only 1.8% to 5% THC. Moreover, weaker marijuana requires more draws and releases more CO than marijuana with a higher THC content. Other cannabinoids are not measured, yet they are known to also have a bearing on the medical properties of marijuana. The paper in which the marijuana is rolled is of poor quality. The marijuana is often more than two years old and may not have been stored under conditions that would preserve all its qualities. Finally, the marijuana contains many seeds and other plant debris. Fourth, it is difficult to control the amount of marijuana actually absorbed by the subjects: the way a person draws on the cigarette, whether or not the person is accustomed to smoking, the subject’s preferences and the length of time the subject inhales are factors which can affect the test conditions and which researchers have not yet been able to measure accurately.

It must also be possible to answer the following and other questions:

··               Is there a difference between synthetic cannabinoids and whole marijuana?

··               What is the optimum marijuana profile in a given situation?

··               Do different doses and different forms of ingestion produce significantly different effects?

 

In recent years, analyses of the scientific literature have been conducted by the Institute of Medicine in the United States and the British Medical Society and in various government reports in England, the Netherlands and elsewhere. The Institute of Medicine concluded that there is evidence of the therapeutic potential of marijuana as an analgesic, antiemetic and appetite stimulant. It noted, however, that smoking is a difficult way to control the ingestion of marijuana and also has side effects related specifically to its carcinogenic potential and the link with respiratory diseases. The institute also found that the psychoactive effects of marijuana are sometimes, but not always, beneficial for some patients. Finally, the institute pointed out that smoking marijuana should not be recommended over the long term because of the potential mental effects, but could be prescribed for persons with terminal or degenerative diseases, where long-term considerations are secondary. In the Netherlands, the National Health Council issued a notice in 1995 stating that scientific evidence on medical use of marijuana was insufficient because of poor research and uncertainty as to the properties of smoked marijuana. The council also noted that marijuana could have therapeutic applications in the following areas: nausea and vomiting related to chemotherapy, appetite stimulation for people with AIDS or cancer, multiple sclerosis and glaucoma. In 2001, the Netherlands created a medical marijuana bureau in the ministry of health and began clinical studies. In England, the House of Lords has taken a position similar to that of the Institute of Medicine in the United States, and the Ministry of Health is currently conducting at least one clinical study.

Clearly, not enough is known about marijuana to establish it as a drug in the strict sense of the word, and we only have partial knowledge of cannabinoids. Most cannabinoids are a single cannabinoid compound, whereas marijuana contains many substances the effects of which interact to produce the therapeutic effects. Yet researchers have still not specifically identified the role of the various cannabinoids. Patients who use synthetic dronabinol or nabilone-based compounds generally report not feeling the same beneficial effects as when they smoke marijuana. It may take longer for the effects to be felt, and the effects may be less specific. Further, isolating only one of the components of marijuana could, according to some studies, increase the risk of panic attacks and even marijuana-induced psychosis.

 

A significant benefit of whole marijuana is that it can be delivered in smoked format, with a rapid onset of action and a tritable effect by the patient. […] In practice, both patients and oncologists report that smoked marijuana is somewhat more effective than and as safe as the legally available oral cannabinoids. Another major difference between marijuana and THC, besides the availability of a smokeable, titratable delivery system with whole marijuana, is that 9-THC alone can produce the relatively common effects of anxiety disorder and panic attack. […] The adverse effects can also occur with marijuana use, but are felt to be diminished by the presence of cannabidiol, a nonpsychoactive compound with antipsychotic properties. [2][21]

 

Finally, the cost of synthetic compounds, which is much higher, has to be taken into account.

The advantages of smoked marijuana are that patients can determine the necessary dose on their own and feel the effects more quickly, while limiting the adverse side effects other than the effect on the respiratory system. It should be noted in passing the importance of self-regulation by patients: most of the clinical cases reported and most of the testimony from compassion club representatives agree that patients prefer to use marijuana with a higher THC content than recreational marijuana but only ingest the quantity they need to achieve the calming effects. However, the problems related to specific knowledge of the effectiveness and quality of marijuana limit the ability of physicians to prescribe the appropriate dose. More advanced knowledge of smoked marijuana pertains to the degree of safety, although there is variation in interpretation of the data. We generally concur in the finding of Professor Scholten:

 

Cannabis use for medicinal reasons by patients with a somatic disease is relatively safe, on condition that it is not smoked; when smoked it has the same carcinogenic potential as tobacco. The alternatives are oral administration or inhalation using a vaporiser.

The acute toxicity of cannabis is very low; it is almost impossible to die of an overdose (users would have to eat or smoke their own weight in fresh cannabis, or 7,500 grams of dried cannabis to achieve this). The principal side effects in therapeutic use are psychosis and euphoria. Little is known about this drug’s addictive effect in medical use, though experience with the use of morphine for pain relief has shown that the risk of psychological addiction is low – much lower than when used as a stimulant. As the addictive effect of cannabis is also quite low when used as a stimulant, it may be assumed that this will always be very low in a medical setting.

When estimating the chronic toxicity of cannabis, it should be borne in mind that the doses used in therapeutic applications will probably be lower than those used for "recreational" purposes, decreasing the risks of side effects. [3][22]

 

Does this mean that medical use of marijuana, smoking in particular, should be discouraged or even banned? The last section addresses this question.