Nicotine delivery kinetics and abuse liability.

It is well established that nicotine meets all criteria of a highly addictive drug. However, as recognized by the U.S. surgeon general, the nicotine delivery system itself is an important determinant of the toxic and addictive effects engendered by nicotine use. Therefore, altering the form of nicotine dosing may allow for selective therapeutic action in efforts to develop safer and less addictive nicotine replacement therapies. While it is the case that initial tobacco use often escalates to compulsive use accompanied by tolerance and physical dependence, this is not usually observed with nicotine replacement therapies. These observations are consistent with laboratory data indicating that (a) nicotine polacrilex and transdermal systems deliver nicotine more slowly and at lower dose levels than tobacco-based forms, and (b) human data suggesting that the abuse liability of these systems is substantially lower than that of the tobacco-based nicotine delivery systems. Because the drug dosage form can be systematically manipulated and evaluated, further research in developing alternative nicotine delivery forms may hold substantial promise in the treatment of tobacco dependence. Psychological research methods can play an important part in their evaluation.