cannabis

When marijuana is smoked, THC in the form of an aerosol in the inhaled smoke is absorbed within seconds and delivered to the brain rapidly and efficiently as would be expected of a very lipid-soluble drug marijuana seeds. Peak venous blood levels of 75 to 150 nanograms per milliliter (ng/mL) of plasma appear about the time smoking is finished (Agurell et al. 1984, 1986; Huestis et al. 1992a, 1992b). Arterial concentrations of THC have not been measured but would be expected to be much higher initially than venous levels, as is the case with smoked nicotine or smoked cocaine. Oral ingestion of THC or marijuana is quite different than smoking. Maximum THC and other cannabinoid blood levels are only reached 1 to 3 hours after an oral dose (Adams and Martin 1996; Agurell et al. 1984, 1986).

The last question, Question 4, concerning the special issues involved in conducting clinical trials with marijuana, was particularly difficult. There was considerable discussion and debate as to whether smoked marijuana (with the inherent health risks of smoking) would need to demonstrate clear superiority or some unique benefit compared with other medications currently available for these conditions. The Expert Group concluded that smoked marijuana should be held to standards equivalent to other medications for efficacy and safety considerations. Moreover, there might be some patient populations; e.g. graines cannabis, cancer patients experiencing nausea and vomiting during chemotherapy, for whom the inhalation route might offer advantages over the currently available capsule formulation. This raises many issues concerning the best mode of administration.