Timirdine (also known as EGY-4201) is an iminothiazolidine derivative patented by EGIS Gyogyszergyar as an antidepressant. In the behavioral despair model and in antagonizing the effect of tetrabenazine, Timirdine efficacy was considerably higher than that of several tricyclic and second-generation antidepressant drugs. Timirdine was also active in inhibiting the hypothermic effect of apomorphine. It potentiated the lethal effect of yohimbine, the hypermotility provoked by L-dopa, and the stereotypy induced by D-amphetamine. In contrast to amitriptyline and nomifensine, Timirdine showed neither sedative nor stimulant actions on spontaneous and conditioned behavior.