Pregnanediol is a chief steroid metabolite of progesterone that is biologically inactive and occurs as pregnanediol glucuronate in the urine. Pregnanediol has two hydroxyl groups, at 3-alpha and 20-alpha. A test can be done to measure the amount of pregnanediol in urine. The urine test offers an indirect way to measure progesterone levels in the body. It is a standard in the colorimetric determination of urinary pregnanediol in clinical laboratories.

Napamezole [WIN 51181] is a potent alpha-2 adrenergic receptor antagonist and a selective inhibitor of 5-hydroxytryptamine re-uptake in vitro. Napamezole was at the phase I stage of development with Sanofi Winthrop (formerly known as Sterling Drug before it was purchased by Sanofi) in the USA as a treatment for depression. The alpha adrenergic antagonist activity of napamezole was determined in vitro in rat brain receptor binding assay using [3H]clonidine and [3H]prazosin for alpha-2 and alpha-1 receptors, respectively. The Ki values for napamezole were 28 nM (alpha-2) and 93 nM (alpha-1).

Butanserin is the potent and selective alpha 1-adrenoceptor antagonist.

Spiroxatrine is a drug which acts as a selective antagonist at both the 5-HT1A receptor and the α2 adrenergic receptor. Spiroxatrine was identified as a moderately potent but non-selective agonist at the human nociceptin/orphanin FQ receptor, ORL1

Coumazoline is a vasoconstrictor developed as a nasal decongestant by a French corporation Labez. Intravenous administration of the compound to dogs lead to a marked and prolonged drop in the temperature of the gingival mucosa. In rats, coumazoline caused slowing of the dye diffusion on the surface of the skin. The compound did not influence the ciliary motility, as was measured on an isolated guinea pig trachea.

Dexlofexidine is an isomer “+“ of lofexidine, which is agonist of alpha 2-adrenoceptor, but in 10 times less potent than the other isomer, levlofexidine.

Esproquine is a tetrahydroisoquinoline derivative. It exerts positive inotropic effect and increases arterial pressure.

Deriglidole was reported to inhibit alpha 2-adrenoceptors and ATP-sensitive K+ channels in mouse pancreatic B-cells, and to increase insulin release. The effects of deriglidole are stereoselective on alpha 2-adrenoceptors, but not on ATP-sensitive K+ channels of pancreatic B-cells. Deriglidole had been in phase II clinical trial for the treatment of diabetes mellitus type II in France. However, the study was discontinued.

Domazoline is anticholinergic agent. It is antazoline derivative. Domazoline is antihistaminic, local vasoconstrictor and nasal decongestant. As a hair stiffener, it was used in depilatory preparations.

Upidosin [REC 152739, REC 22009] is an α1-blocker that was in phase II trials with Recordati in Belgium and Israel for the treatment of benign prostatic hyperplasia. When evaluated in radioligand binding assays with expressed animal or human alpha-1 ARs, Upidosin shows marked to moderate selectivity for the alpha-1a AR subtype. Its affinity for the recombinant alpha-2 AR subtypes or native dopaminergic D2 receptor was about 100-fold lower than that for alpha-1a AR subtype.