ABSTRACT
Optimal dosage and timing of administration has yet to be established for all indications. Routes of administration of cannabinoids also remain problematic. Anecdotal reports suggest that cannabis is more effective and has fewer unwanted effects when it is smoked than when it is taken orally (Grinspoon and Bakalar, 1993). This may be due to a number of factors. First, cannabis is much more rapidly absorbed when inhaled than when taken orally (see Pharmacokinetics, p. 11–15). Secondly, other cannabinoids in cannabis smoke may enhance or modify the effects of THC. Thirdly, patients can exert a degree of control over the amounts of cannabinoids absorbed and hence over the nature and intensity of the symptoms they experience optimising the balance between beneficial and unpleasant effects. The health risks associated with smoking tobacco have been well documented, and many of the same constituents are present in cannabis smoke, including most of the known carcinogens (see Table 2). An increase in carboxyhaemoglobin as well as tar has also been described (Tau-Chin Wu et al., 1988). However, fully effective aerosol preparations of cannabinoids have yet to be developed, and research in this area is badly needed, so that cannabinoids can be administered quickly. Inhalation may also improve bioavailability in comparison with the oral route. Furthermore, if improved routes of administration are not developed, patients 74may resort to illegally smoking cannabis with the associated health and social risks.
