2. Cannabis in Switzerland: The current situation
2.5 The medical importance of cannabis
Note on this chapter: This report is concerned primarily with the use of cannabis as a recreational drug. Whether cannabis products can be used beneficially in the medical treatment of patients is a completely different question which must be considered separately from both a technical and a legal point of view. However, Chapter 2.5.2 provides a brief summary of the current state of knowledge, and the conclusions at the end of this report will also touch on this aspect. The paragraphs printed in italics and smaller typeface are intended for those with a special interest in this field and may be omitted without fear of losing the context.
The first written evidence of cannabis being used in medicine is probably a Chinese handbook of botany and healing some 4,700 years old. Cannabis was mentioned in herbals from the 16th century. It was used in popular medicine from the time of the first crusade and featured in the medicine practiced by monks in many monasteries. It was used to treat rheumatic and bronchial disorders, and was also prescribed generally as a substitute for opium. In the 19th century it was also a popular treatment for migraine, neuralgia, epileptiform convulsions, insomnia and other conditions. Marijuana was the most commonly used pain killer in America until 1898, when it was faced with stiff competition from Aspirin and was ultimately replaced by a wide range of new, synthetic medications. Between 1842 and 1900, cannabis preparations accounted for half of all medicines sold in America
(Herer 1993). More than 100 different cannabis- based medicines were available in Europe, most of them in Switzerland as well, between 1850 and 1950
(Fankhauser 1996). Difficulty in dosing these preparations, paradoxical effects and the development of more effective products led to a decline in prescriptions for cannabis even before prohibition finally put an end to its use
(Mikuriya 1973, Mikuriya 1982, Springer 1982). Today doctors are not allowed to prescribe cannabis or cannabinoids (the legal situation is explained in Chapter 2.6.4.3). Scientific research involving cannabis requires a special license from the Swiss Federal Office of Public Health. The Paraplegic Center in Basel is currently running a study to investigate dronabinol in the treatment of painful muscle spasms in paraplegics; initial results are promising.
Below is a brief summary of two medical aspects of cannabis:
- A review of the major scientific findings relating to the therapeutic use of cannabis ( 9 tetrahydrocannabinol [THC] and synthetic cannabis products);
- An overview of medical experience with cannabis poisoning in acute medical care.
2.5.2 Investigation of the therapeutic action of cannabis
In recent years, the prescription of cannabis and cannabis- based active principles for therapeutic purposes has become a recurrent and growing focus of scientific, medical and political interest. Some countries permit cannabis to be prescribed under various conditions, usually for medical trials or on a named- patient basis; a treatment regimen for a distinct indication has been established only in very few cases. The only indications for which dronabinol (delta- 9- THC) has received regulatory approval for routine use to date are to stimulate appetite in AIDS patients and to control nausea and vomiting in patients undergoing chemotherapy in whom other drugs have proven ineffective. Dronabinol was launched in the USA in 1986 under the name Marinol and has since been approved in Canada (1990), Australia (1995), Israel and South Africa. It is available for license in Germany, Belgium, Japan and Switzerland (Kleiner and Kovar 1998).
In 1997 the National Institutes of Health (NIH) in the USA reviewed the available literature on the therapeutic value of cannabis and the need for further research. The information below is based on the expert report subsequently submitted to the NIH (Beaver et al 1997). A further summary has been complied by Gowing et al (1998).
Pain management: Two controlled studies of patients with cancer pain were carried out with oral THC vs. placebo. Although THC had an analgesic effect, it was difficult to dose because of the very narrow therapeutic window between ineffective underdosing and the adverse effects associated with overdosage. No studies have been carried out with smoked or otherwise inhaled cannabis.
Neurological disorders: There is evidence that cannabis is effective against the spasticity associated with multiple sclerosis and has a certain potential in the treatment of epilepsy, but no clinical studies have been carried out in either indication. Cannabis has proved ineffective in attempts to treat Parkinson's disease and Huntington's disease.
Nausea and vomiting caused by chemotherapy in cancer patients: THC administered orally is more effective than placebo but less effective than drugs such as metoclopramide. The relative efficacy of oral THC or smoked marijuana compared with newer anti- emetics has not been studied. Dronabinol is authorized in the USA for patients in whom conventional therapy to counter nausea and vomiting is ineffective.
Glaucoma: Local administration of THC reduces intraocular pressure in healthy subjects and glaucoma patients without affecting blood pressure or mood. The mechanism of action is unknown.
Cachexia (wasting associated with serious illness): Clinical studies have demonstrated a connection between cannabis use and increased appetite in healthy subjects. THC can bring about weight gain in wasted AIDS and cancer patients. Dronabinol is approved in the US for the treatment of AIDS- related anorexia.
Further research is recommended in all these indications. In particular, controlled clinical trials are needed which focus both on pharmaceutical products and on smoked cannabis.
2.5.3 Cannabis poisoning in medical emergency statistics
A completely different aspect of any medical evaluation of cannabis must be the experience gained with acute intoxications encountered in critical care situations. There are no systematic medical statistics documenting cases of acute poisoning and their outcome, but the figures compiled by the Swiss Toxicology Information Center and studies carried out by two hospital emergency departments (Berne and St. Gallen) provide a good indication of the current situation.
2.5.3.1 Swiss Toxicology Information Center
In 1997 the Swiss Toxicology Information Center handled 87 enquiries about cannabis poisoning (66 in 1996 and 60 in 1995). Between 70 and 75 percent of these cases involved simple intoxication with cannabis, between 25 and 30 percent involved another substance as well. Of the enquiries received, 60 percent came from doctors, 40 percent from lay people. More detailed analysis only started in 1997. Of the cases of simple intoxication, two had an asymptomatic course, eight involved moderately severe symptoms and one involved severe symptoms. All the patients survived.
2.5.3.2 Clinical trials in Switzerland
a) Study in Berne
A retrospective study analyzed all the cases of acute intoxication with illegal drugs admitted to the emergency department of the Inselspital Hospital in Berne during a 183- day period in 1989 and 1990. The study covered a total of 157 patients, among whom cannabis featured fewer than four times (< 1.6 percent) in combination with another substance. A total of 257 different substances were recorded for these patients. Cannabis showed no dangerous effects in this study.
b) Study in St. Gallen
A five- year prospective study (1993 - 1997) of 20,220 medical emergencies at St. Gallen cantonal hospital showed that intoxication with cannabis alone accounted for just three emergencies. This is equivalent to 0.015 percent of all medical emergencies. All three patients presented to the out- patients department with mild mental disturbances. The symptoms regressed spontaneously within a short time in all patients. Cannabis was detected in a total of 21 patients (0. 1 percent of all medical emergencies), three times as the sole cause of poisoning, once in combination with other illegal drugs, and 14 times in combination with illegal drugs, prescribed medication and alcohol. There were no deaths or serious complications related to cannabis.
Literature
Beaver WT, Buring J et al (1997) : Workshop on the medical utility of marijuana. Report to the Director, National Institutes of Health, by the Ad Hoc Group of Experts
British Medical Association (1997). Therapeutic use of cannabis, HAP. Hall W, Solowij N et al (1995). National Drug and Alcohol Research Center, Monograph Series No. 25, Australian Government Publishing Service, Canberra.
Fankhauser M (1996). Haschisch als Medikament. Dissertation, University of Berne. Gowing LR, Ali RL et al (1998): Commentary. Therapeutic use of cannabis: clarifying the debate. Drug and Alcohol Review 17: 445- 452.
Herer J (1993). Die Wiederentdeckung der Nutzpflanze Hanf; Cannabis, Marihuana, Zweitausendeins, Frankfurt am Main.
House of Lords/ Subcommittee on Cannabis (1998). Cannabis: the scientific evidence and medical evidence. Science and Technology, Ninth Report.
Kleiber D, Kovar KA (1997). Auswirkungen des Cannabiskonsums. Eine Expertise zu pharmakologischen und psycho- sozialen Konsequenzen. Wissenschaftliche Verlagsgesellschaft, Stuttgart.
Mikuriya TH (ed.) (1973) : Marijuana. Medical papers, 1839- 1972. Oakland, California. Mikuriya TH (1982) : Die Bedeutung des Cannabis in der Geschichte der Medizin. In: Burian W, Eisenbach- Stangl I (ed.) Haschisch: Prohibition oder Legalisierung. Beltz, Weinheim.
Roques B, (May 1998). Problèmes posés par la dangerosité des ”drogues”, Report to the Secretary of State for Health, France.
Springer A (1982). Zur Kultur- und Zeitgeschichte des Cannabis. In: Burian W, Eisenbach- Stangl I (ed.) Haschisch: Prohibition oder Legalisierung. Beltz, Weinheim.
Source for St. Gallen study: Stillhard U. Akute Intoxikationen mit illegalen Drogen am Kantonsspital St. Gallen von 1993 bis 1997: Veränderungen in der Demographie und im Verlauf. Dissertation at the Faculty of Medicine, University of Basel, 1998.