Amfonelic acid, a derivative of nalidixic acid, was originally developed as a central nervous system stimulant. It is a highly potent nonamphetamine stimulant whose actions are inhibited by reserpine but not by the tyrosine hydroxylase inhibitor, a-methyltyrosine. Additionally, it enhances the impacts of antipsychotic medicines such as haloperidol, trifluoperazine, and spiperone.