Orrin Devinsky,Benjamin J. Whalley, and Vincenzo Di Marzo
Neurotherapeutics. 2015 September 23; 12(4): 910.
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“…Dronabinol (Marinol) is the only cannabinoid-based medicine that is approved by the US Food and Drug Administration, with an indication for loss of appetite associated with weight loss in patients with AIDS and those receiving chemotherapy [2]. Dronabinol is the synthetic active enantiomer of the plant-derived cannabinoid, Δ9-tetrahydocannabinol (THC) and works via cannabinoid type 1 (CB1) and type 2 (CB2) receptors (CB1R and CB2R, respectively), where it acts as a partial agonist [3]. In more than 20 European and other countries outside the US, nabiximols (Sativex; GW Pharmaceuticals, Cambridge, UK) is approved to treat spasticity in patients with multiple sclerosis [4]. Nabiximols is a mixture extracts of two varieties of the cannabis plant, one predominantly containing THC and the other cannabidiol (CBD). Interestingly, and contrary to popular misconception, CBD is not a potent ligand at either CB1R or CB2R, although occasionally it can functionally modulate the consequences of mammalian endocannabinoid system stimulation in which the 2 cannabinoid receptors play a pivotal role [5]. In fact, CBD has several noncannabinoid receptor molecular targets and thus exemplifies the diverse pharmacology of the 500 discrete components of the cannabis plant, of which nearly 100 have cannabinoid-like chemical structures.
The relative scarcity of proven cannabis-based therapies is not due to data that show that cannabinoids are ineffective or unsafe, but rather reflects a poverty of medical interest and a failure by pharmaceutical companies arising from regulatory restrictions compounded by limits for patent rights on plant cannabinoid-containing preparations that have been used medicinally for millennia, as is the case for most natural products….”