Described herein is a method for treating a central nervous system disorder, said method comprising steps of first transnasally administering to or immediately adjacent the sphenopalatine ganglion a first pharmaceutical agent that effectively enhances permeability of the blood-brain barrier; and thereafter administering a second pharmaceutical agent with known efficacious value for action upon central nervous system tissue. The central nervous system disorder may be related directly to the brain or to other central nervous system tissues and cells.