Cannabis has a long history of medical use in various countries (Grinspoon & Bakalar, 1993). Cannabis was used to treat a variety of human ills in folk and formal medicine for thousands of years in Turkey, South America, Egypt, India, the Malays, Burma and Siam (Hall & Degenhardt, 2003; Mechoulam, 1986; Anslinger & Cooper, 1937). In the early 1800s, United States physicians used cannabis extracts to produce a tonic for both medicinal and recreational purposes. However, in 1937 its use as an intoxicant was prohibited by the Marijuana Tax Act. Nevertheless, in the same year tinctures of cannabis were still cited in the United States Pharmacopeia and National Formulary’s list of therapeutic drugs.
Until 1937 a nerve tonic produced from the cannabis plant was legally retailed in South Africa. For many years, mankind here attached medicinal value to the cannabis plant and used it for many ailments such as epilepsy, asthma, heart attack, multiple sclerosis and cancer (Spruit & Van Laar, 1997). Some religious groups such as the Rastafarians refer to it as the holy plant that induces calmness and inner peace. Some traditional healers (e.g. ngaka ya malopo) and some indigenous religious leaders in South Africa also assert that cannabis helps people to “see into the future” and to “hear voices” of prophecy. This is in keeping with Hanson and Venturelli’s (1998:372) statement: “A subjective euphoric effect associated with marijuana use is the ongoing social psychological experiences incurred while intoxicated with marijuana. It includes both the user’s altered state of consciousness and his or her perceptions while intoxicated.” The following therapeutic benefits have been listed with regard to cannabis use:
Drocannabinol is used to stimulate appetite and to assist AIDS patients to gain weight (Beal, Olson, Laubenstein et al., 1995). Hall and Degenhardt (2003), however, point out that some patients do not like the psychoactive effects of drocannabinol; they find it difficult to titrate their oral dose because of the delayed onset and prolonged duration of its effects.
Glaucoma is caused by elevated intra-ocular pressure (IOP), which produces blindness if untreated. Drocannabinol taken orally or intravenously reduces IOP by 25%, but this effect lasts only for three to four hours (Hall & Degenhardt, 2003). Cannabis lowers glaucoma-associated IOP, even though it does not cure the condition or reverse blindness.
Cannabis smoke results in bronchodilation. This means that it dilates the air passages and thus achieves an anti-asthmatic effect. Some researchers have observed that short-term smoking of cannabis improves the breathing of asthma patients.
Some studies have shown that muscle spasms are relieved when patients with muscle disorders, such as multiple sclerosis, use cannabis (Pertwee, 2002). While several other studies have provided some support, Hall and Degenhardt (2003:691) state: “There are too few clinical trials to evaluate efficacy.”
Cannabis has both convulsant and anti-convulsant properties. It has been considered in the prevention of epileptic seizures.
Cannabis and the synthetic cannabinoid synthexyl have been used successfully in Great Britain as specific euphoriants for the treatment of depression.
A small number of controlled trials in humans suggest that drocannabinol and other cannabinoids have analgesic effects in acute post-operative and chronic pain, being equivalent to 60 mg codein (Hall & Degenhardt, 2003; Bagshaw & Hagen, 2002; Campbell, Tramer & Carrol, 2001). However, according to these authors, some patients report adverse psychotropic effects from these cannabinoids. Hanson and Venturelli (1998) also note that the pain-relieving potency of cannabis has not been carefully studied and compared with the pain-relieving properties of other analgesics such as the narcotics or aspirin-type drugs. Indeed, various researchers have emphatically stated that cannabis and related products must be rigorously tested for toxicity and therapeutic effectiveness, a process which is “timeconsuming, expensive and not worthwhile if other drugs are already available that offer therapeutic efficacy comparable to, or better than, the marijuana substances. In addition, concerns about the abuse potential and the social stigma associated with marijuana need to be considered” (Hanson & Venturelli, 1998:385).
Cannabis (THC) or related drugs have often been used for the symptomatic relief of extreme nausea and vomiting that tend to accompany cancer chemotherapy (Hall & Degenhardt, 2003). In Canada, in the late 1970s and early l980s, for example, cannabis was used medically by hundreds of patients (mainly in the form of synthetic tetrahydrocannabinol) in state projects for the treatment of nausea and vomiting in cancer chemotherapy. This practice was, however, discontinued “because each state program had to comply with an enormous federal paperwork burden that was more than the physicians and administrators involved could bear” (Grinspoon, 1998:386).
Hall and Degenhardt (2003) further state that newer anti-emetics, such as ondansetron, appear to provide better control over nausea and vomiting than drocannabinol, with fewer adverse effects. There may be value in exploring the efficacy of combining ondansetron and drocannabinol to manage poorly controlled or delayed vomiting (Hall & Degenhardt, 2003).