Tiamenidine (also known as HOE 440) is a diazacycloalkene derivative patented by Farbwerke Hoechst A.-G. as 2 alpha-sympathomimetic antihypertensive agents. In preclinical models, tiamenidine induces hypotension and bradycardia in renal hypertensive cats and rats and in normal rats and dogs. Furthermore, Tiamenidine inhibits the liberation of norepinephrine from nerves leading to the heart and suppress sympathetic circulatory reflexes in dogs. In clinical trials, Tiamenidine exerts favor influences on systolic and diastolic blood pressure, and reduces plasma noradrenaline and adrenaline levels and suppresses plasma renin activity. Unfortunately, during the withdrawal of Tiamenidine, there is a rebound of blood pressure and plasma noradrenaline and adrenaline, overshooting baseline levels.

Azepexole (or previously known as B-HT 933), a selective alpha 2-adrenoceptor agonist that was studied for the man with physiological tremor. It was shown that the drug produced sedation compared to placebo but not when compared to pre-treatment values. Some studies also have revealed the anti-tussive and antihypertensive properties of azepexole.

Taprizosin (also known as UK-338,003) is an alpha1A-adrenoceptor antagonist that was developed for the treatment of benign prostatic hyperplasia. However, this compound possesses poor oral absorption.

Efaroxan (RX 821037) is a potent and selective alpha(2)-adrenoceptor antagonist. Additionally, Efaroxan is a selective antagonist at the imidazoline I1 receptor. Efaroxan promotes insulin secretion, in the absence of exogenous agonists, by a mechanism that involves inhibition of ATP-regulated K+ channels. Efaroxan was in clinical trials for the treatment of diabetes mellitus however its development has been discontinued.

Cirazoline is an agonist of alpha1A adrenergic receptor, a partial agonist of alpha1B and alpha1D receptors, and an antagonist of alpha2 adrenergic receptors. Cirazoline was used to study the biologic function of adrenergic receptors. Injection of cirazoline into to the paravenricular hypothalamic nucleus of rats suppressed food and water intake. Cirazoline caused a large renal vasopressor response in rats. Systemic administration of cirazoline impaired spatial working memory in monkeys.

Tinazoline is an imidazole derivative patented by Ciba-Geigy A.-G. as vasoconstrictors, particularly as nasal decongestants in the treatment of common cold. Tinazoline showing potent and long-acting vasoconstrictor activity on several vascular beds in dogs, guinea-pigs, cats, and rabbits. The vasoconstrictor effect has been shown in animals to be due to a stimulation of the 1-adrenoceptors and the compound does not exhibit any B-adrenoceptor agonist activity.

Mivazerol is a new and selective alpha 2-adrenoceptor agonist, devoid of hypotensive effects, which has been designed to prevent adverse cardiac outcome in perioperative patients with, or at risk coronary artery disease. This compound, which lacks hypotensive effects, has been demonstrated to prevent hyperadrenergic activity and myocardial ischemia in perioperative patients and tachycardia in rats at emergence from halothane anesthesia. This type of ischemia, frequently encountered in postoperative patients, is considered to be a consequence of stress-induced hyperactivation of the sympathetic system. Anti-ischemic effects of this compound have been demonstrated in different animal models of myocardial ischemia, and Mivazerol has also been shown to improve exercise-induced ischemia in patients with angina pectoris.