CP 945,598 (hydrochloride) is a selective antagonist of the cannabinoid receptor CB with a K value of 0.7 nM and demonstrates relatively low affinity for CB receptors (K = 7.6 µM). It is reported to reverse cannabinoid agonist-mediated responses (i.e., hypo-locomotion, hypothermia, analgesia, and catalepsy), to reduce food intake, and to increase energy expenditure as well as fat oxidation in rats.