Tolonidine is a derivative of imidazoline. Tolonidine is orally active and has been shown to possess hypotensive and antihypertensive properties[1].
In the anesthetized dog, tolonidine administered i.v. decreases the amplitude of ventricular contractions, reduces aortic blood flow and increases peripheral vascular resistances[1]. In the bivagotomized pithed rat, tolonidine induces a long-lasting increase in blood pressure with no secondary hypotension, thus suggesting peripheral sympathomimetic properties[1].
[1]. Cosnier D, et al. Pharmacological properties of 2-(2-chloro-p-toluidino)-2-imidazoline-nitrate (tolonidine), a new antihypertensive agent. II. Action on cardiac contraction, circulatory parameters, autonomic receptors and diuresis. Arzneimittelforschung. 1975 Nov;25(11):1802-6.