Puerarin (7, 4’-dihydroxyisolavone-8-β-glucopyranoside) is an active isoflavone extracted from the roots of Pueraria lobata (Willd.) Ohwi. Puerarin is widely used in traditional Chinese medicine, and is clinically used in China for the treatment of coronary artery disease, heart failure, hypertension and myocardial infarction. It has been reported that puerarin had therapeutic effects on diabetes mellitus, arteriosclerosis and myocardial ischemia in animals. Puerarin demonstrated beta-adrenergic receptor blocking effect. On the other hand, puerarin stimulated alpha1-adrenoreceptor to increase glucose uptake into cultured C2C12 cells of mice. Puerarin has been investigated for the treatment (phase II clinical trials) of Alcohol Abuse, Rheumatoid Arthritis and Hypertension.

Zolertine is an alpha-adrenergic receptor antagonist that acts as an antihypertensive agent. Its effect was studied in animals in vivo and in vitro. Zolertine considerably decreased systemic blood pressure in mecamylamine hypertensive dogs in a dose-related fashion. Using the intravital microscopic method in rat's mesocygeus microvasculature a direct relationship between zolertine dosage and blockade was demonstrated as well as an inverse relationship between time of action of zolertine and percentage of vasoconstriction caused by noradrenaline. When only zolertine was applied, it caused a small vasoconstriction that decreased as its concentration increased which could be due to its ability to antagonize alpha receptor responses, but not beta responses. Zolertine is a more active alpha blocker than azapetin, a blocker used in medical practice. Competition binding experiments using the alpha1-adrenoceptor antagonist [3H] prazosin showed a zolertine pKi of 6.81 +/- 0.02 in rat liver (alpha1B-adrenoceptors) and 6.35 +/- 0.04 in rabbit liver (alpha1A-adrenoceptors) membranes. Zolertine showed higher affinity for alpha1D-adrenoceptors compared to alpha1A-adrenoceptors, while it had an intermediate affinity for alpha1B-adrenoceptors. The ability of the alpha1-adrenoceptor antagonist zolertine to block alpha1D-adrenoceptor-mediated constriction in different vessels of Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats may explain its antihypertensive efficacy despite its low order of potency.

Clorotepine (aka octoclothepin or octoclothepine) is an antipsychotic from the tricyclic group derived from perathiepin. It was originally developed in 1965 and marketed in the Czech Republic by Spofa in or around 1971 for the treatment of schizophrenic psychosis. Clorotepine has a high affinity for the dopamine (D1, D2, D3, D4), receptors the serotonin 5-HT (2A, 2B, 2C, 6, 7) receptors, the alpha-adrenergic receptors (1A, 1B, 1D), and the histamine H1 receptors. In most instances, it acts as an antagonist (or inverse agonist). Clorotepine will also block the reuptake of norepinephrine by inhibiting the norepinephrine transporter.

Dabuzalgron is an orally active and selective alpha1A/1L-adrenoreceptor partial agonist, developed by Roche. In anesthetized micropigs and rabbits, dabuzalgron produced non-selective, dose-dependent increases in intraurethral and arterial blood pressures. In conscious micropigs, both agents produced dose-dependent increases in urethral tension. Dabuzalgron was investigated in a clinical study in women with stress urinary incontinence (SUI). It was demonstrated that 1.5 mg of the drug administered twice daily lead to a significantly lower mean weekly number of SUI episodes with little or no cardiovascular effect. Despite positive results, no development of the drug was reported by Roche.

Corynanthine is one of the two diastereomers of yohimbine (the other is alpha-yohimbine). Corynanthine is an antagonist of the alpha-1, alpha-2A and alpha-2C adrenergic receptors showing greater selectivity for the alpha-1 adrenergic receptor. Corynanthine was tested as the active ingredient of eye drops in a small clinical trial for Ocular hypertension where formulations of 2% and 5% demonstrated relief of symptoms.

Methoxamine is an alpha-adrenergic agonist that induces prolonged peripheral vasoconstriction, and can also stimulate the release of arginine vasopressin in humans. In clinical trials, methoxamine was found to improve fecal incontinence. It had been marketed by Glaxo-Smith-Kline under the brand name Vasoxyl but has been discontinued. Methoxamine was also found to stimulate the induction of hiPSC-derived hepatoblasts to ALBUMIN+ cells.

Naftopidil (INN, marketed under the brand name Flivas) is a drug used in benign prostatic hypertrophy which acts as a selective alpha1-adrenergic receptor antagonist, has been used for the treatment of benign prostatic obstruction and benign prostatic hyperplasia (BPH) associated lower urinary tract symptoms (LUTS). The Japanese Ministry of Health, Labor and Welfare approved naftopidil for treating men with BPH in 1996. Although well-designed, randomized studies are warranted to confirm the long-term outcomes and effector/target of naftopidil, the α1A-antagonist naftopidil, which also blocks α1D-adrenoceptor, improves voiding symptoms, and may also be useful for the management of men with storage symptoms represented by nocturia, retrieving their quality of life impaired by BPH-associated LUTS. The selective alpha1D-blocker naftopidil can significantly facilitate spontaneous passage of distal ureteral stones with few side effects, providing a new choice for medical expulsive therapy.