Oxpheneridine is a mu opioid receptor agonist that possesses the spasmolytic activity and acts as a narcotic analgesic. However, this compound was not listed as an illegal drug, because of its poor solubility and low doses didn’t produce any addiction. Information about the current use of this drug is not available.

Prinaberel is a selective agonist of estrogen receptor beta. Although initially developed for the treatment of endometriosis, the drug was also shown to be effective in vitro in other inflammatory diseases. Phase II clinical studied revealed its effectiveness in case of Crohn's disease and endometriosis, but the drug failed to demonstrate antiinflammatory efficacy in RA patients.

Resiquimod is an imidazoquinolinamine and Toll-like receptor (TLR) agonist with potential immune response modifying activity. Resiquimod exerts its effect through the TLR signaling pathway by binding to and activating TLR7 and 8 mainly on dendritic cells, macrophages, and B-lymphocytes. This induces the nuclear translocation of the transcription activator NF-kB as well as activation of other transcription factors. This may lead to an increase in mRNA levels and subsequent production of cytokines, especially interferon-alpha (INF-a) and other cytokines, thereby enhancing T-helper 1 (Th1) immune responses. In addition, topical application of resiquimod appears to activate Langerhans' cells, leading to an enhanced activation of T-lymphocytes. Resiquimod is used as a topical gel[1] in the treatment of skin lesions[2] such as those caused by the herpes simplex virus[3][4] and cutaneous T cell lymphoma. Due to its immunostimulatory activity, this agent may potentially be used as a vaccine adjuvant.

Levisoprenaline (l-isoproterenol) is beta1- and beta2-adrenoreceptor agonist. In Japan, continuous inhalation of levisoprenaline is a recommended treatment for pediatric patients with acute severe exacerbation. Compared with salbutamol, l-isoproterenol reduced modified pulmonary index score more rapidly. But in most countries do not recommend continuous inhalation of l-isoproterenol to treat pediatric patients with acute severe exacerbation of asthma due to worsening asthma control. Levisoprenaline was used to cause experimental chronic heart failure in rats.

Carmoxirole is a dopamine D2 receptor agonist with limited central activity that modulates sympathetic activation and subsequently reduces pre-load and afterload in animals. It was shown, that carmoxirole induced beneficial effects on hemodynamic and neurohumoral parameters in heart failure. In addition, experimental evidence showed that carmoxirole lowered blood pressure in various models of hypertension mainly or exclusively through inhibition of noradrenaline release from sympathetic nerve endings. That effect of carmoxirole was mediated by presynaptic dopamine receptors with the characteristic that release inhibition was restricted to low rates of sympathetic nerve discharge.

Normorphine is an opiate analog, specifically the N-demethylated derivative of morphine. It was first described in the 1953 as part of an effort to characterize N-substituted morphine analogs. Normorphine has relatively little opioid activity, but it is a useful intermediate for the production of more potent morphine analogs. It is also a major metabolite of morphine.

Seocalcitol (EB 1089) is a vitamin D analog, and agonist of the vitamin D receptor. Antineoplastic activity of seocalcitol was tested in clinical trials against hepatocellular carcinoma, pancreatic, breast and colorectal cancer. Due to inconsistent results of clinical trials, development of seocalcitol was discontinued by Leo Pharma.

Muraglitazar previously known as BMS-298585 has been identified as a non-thiazolidinedione dual agonist of peroxisome proliferator-activated receptor alpha/gamma. Muraglitazar is currently in clinical trial phase III development for the treatment of type 2 diabetes and dyslipidemia.

ACP-104 or N-Desmethylclozapine (NDMC), or norclozapine is a major metabolite of clozapine, which was developed like a small molecule drug candidate by ACADIA for treatment schizophrenia. ACP-104 combines M1 muscarinic agonist, 5-HT2A inverse agonist, and D2 and D3 dopamine partial agonist in a single compound and, therefore, uniquely addresses what ACADIA believed are the three most promising target mechanisms for treating schizophrenia. Then drug was discontinued, because the study did not meet its primary endpoint of antipsychotic efficacy or any of the secondary endpoints. Neither dose of ACP-104 demonstrated improved efficacy as compared to placebo. The most common adverse events in the treatment arms relative to placebo were increased salivation, tachycardia, and dyspepsia, which were noted to be dose-related. There was no clinically significant decrease in neutrophil counts in the study drug arms.

Tecadenoson is a novel selective A1 adenosine receptor agonist that is currently being evaluated for the conversion of paroxysmal supraventricular tachycardia (PSVT) to sinus rhythm. Adenosine is a naturally occurring compound that stimulates all adenosine receptor subtypes in the body, including the A2 adenosine receptor which lowers blood pressure. In non-clinical trials, tecadenoson selectively stimulated the A1 adenosine receptor in the Atrioventricular node (AV node) and slowed the speed of electrical conduction across the AV node, reducing the number of electrical impulses that reached the ventricle, without affecting blood pressure. Clinical studies to date with intravenous tecadenoson suggest that it may slow the speed of AV nodal conduction by selectively stimulating the A1 adenosine receptor, and may avoid blood pressure lowering by not stimulating the A2 adenosine receptor. Thus, it may be possible to use intravenous tecadenoson to convert patients from PSVT to normal sinus rhythm without lowering blood pressure or causing adverse events related to vasodilation such as flushing, palpitations or a headache.