Anorexic activity of cocaine and coca extract in naive and cocaine tolerant rats.

Dose response curves for reducing limited access food consumption were determined for cocaine HCl IP, cocaine HCl PO, and whole Erythroxylum coca extract PO. The ED50's for cocaine HCl in drug naive rats were 19.6 mg/kg (IP) and 34.6 mg/kg (PO). When the dose of E. coca extract was expressed in terms of cocaine HCl content, the ED50 was 52.6 mg/kg (PO). When dose response curves were determined in rats that had received cocaine (45 mg/kg, PO) for 30 days, a shift to the right in the cocaine HCl curve (an ED50 of 98.4 mg/kg PO) indicated tolerance. However, the shift to the right was less for E. coca extract than for cocaine HCl. Although the anorexic activity of E. coca extract was less than that of an equivalent amount of cocaine in naive rats it was often more than that of equivalent doses of cocaine HCl in tolerant rats. Interaction with other constituents of E. coca extract appears to alter the potency of the cocaine content of the extract in different directions in naive and tolerant rats.