ABSTRACT
Delta-9-tetrahydrocannabinol (119-THC) is commonly accepted as the major psychoactive constituent of Cannabis sativa. However, other components of the plant such as cannabidiol (CBD, see Figure 33.1) can influence its pharmacological activity. 6,24,26
CBD, which constitutes up to 40 percent of marijuana extracts 13 is devoid of the typical marijuana psychological effects,45 but may interact with 119_THC.24,3,12,25,2(),lO,45 Although potentiation of 119-THC effects has been found, this probably involves pharmacokinetic interactions since CBD is a potent inhibitor of hepatic drug metabolism32,4 and increases 119-THC concentrations in the brain.23 Several studies, however, have reported antagonism of 119-THC effects when both compounds are administered concomitantly.24,11,41,46,43
In a study conducted by Zuardi et a1.45 the simultaneous oral administration of CBD (1 mg/kg) with a high 119-THC dose (0.5 mg!kg) in healthy volunteers attenuated the anxiogenic and psychotomimetic symptoms induced by 119-THC, but not the increase in pulse rate. Considering that the dose of
CBO used in this study does not change /19-THC blood levels, 1 it was suggested that CBO blocked /19-THC effects through some intrinsic pharmacological properties. Actually, sedative,34,41,45 hypnotic,28,7 anticonvulsant,5,22,9 neuroprotective,17 and hormonal effects46,42 of CBO alone have been reported in both laboratory animals and humans.
