Liposome encapsulated tetracaine lowers blood glucose

Tetracaine, a local anesthetic, was previously shown to block hormonal stimulation of gluconeogenesis and glycogenolysis ( Friedmann , N. and Rasmussen, H. (1970) Biochim. Biophys. Acta 222, 41-52). In the present studies tetracaine incorporated into liposomes (phospholipid vesicles) was injected into intact rats and epinephrine was administered an hour later. Liposomal tetracaine blocked 50% of the hyperglycemic response. When tetracaine, incorporated into liposomes, was injected into diabetic rats it reduced transiently, but significantly, blood glucose levels. Equivalent doses of free tetracaine were toxic. These studies indicate that liposomal drug administration might be developed into a tool to influence hepatic metabolism and, consequently, blood glucose levels.