Etoxadrol is an NMDA receptor antagonist. It exerts phencyclidine-like properties. Etoxadrol has anticonvulsant and anesthetic activity. Intravenous etoxadrol was clinically tested as an anesthetic.

Nafoxidine is a nonsteroidal antiestrogen available as an investigational agent from the Investigational Drug Branch of the National Cancer Institute. It has been used effectively in the treatment of breast cancer patients. Nafoxidine competes with endogenous estrogen for binding to specific estrogen receptors. This agent also inhibits angiogenesis in some tissues by blocking the effects of fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF); paradoxically, it may enhance angiogenesis in uterine tissue. Nafoxidine also induces oxidative stress, protein kinase C and calcium signaling.

Etoxadrol is an NMDA receptor antagonist. It exerts phencyclidine-like properties. Etoxadrol has anticonvulsant and anesthetic activity. Intravenous etoxadrol was clinically tested as an anesthetic.

Cinanserin is a 5-hydroxytryptamine receptor antagonist; it shows a low affinity to 5-HT2b binding sites and a 4-to 10-fold lower affinity to 5-HT2c receptor binding sites than for 5-HT2a sites. Nevertheless, at concentrations normally used 5-HT2c receptor blocking effects are still likely. Experiments on animal have shown that intravenous administration of cinanserin significantly reduces systemic burn edema and leukocyte-endothelial interactions.

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).

Rimcazole is a carbazole derivative that acts as a sigma receptor antagonist and studied as potential antipsychotic agent for the treatment of acute schizophrenic patients. In open-clinical trials Rimcazole (BW 234U) appears to be effective in acute schizophrenic patients. However, subsequent clinical trials demonstrated that rimcazole lacked efficacy in schizophrenic patients and it is now primarily used as an experimental tool. In addition to its actions as  receptor antagonist, rimcazole also has high affinity for dopamine transporters, and inrecent years it has served as a lead compound for the development of novel dopamine transporter ligands.

Esoxybutynin is (S)-enantiomer of oxybutynin. Esoxybutynin exerts antimuscarinic properties. Racemic oxybutynin is used clinically to treat urinary incontinence. Sepracor was developing (S)-oxybutynin, a single-isomer version of Alza's Ditropan (racemic oxybutynin), a muscarinic acetylcholine receptor antagonist, as a potential treatment for urinary incontinence.

Racemethorphan is racemic mixture of Dextromethorphan and Levomethorphan. Racemethorphan is listed under the Single Convention on Narcotic Drugs 1961 and is therefore listed in the United States as a Controlled Substance, specifically as a Narcotic in Schedule II. Dextromethorphan is a non-narcotic morphine derivative widely used as an antitussive. Dextromethorphan is a cough suppressant in many over-the-counter cold and cough medicines. In 2010, the FDA approved the combination product dextromethorphan/quinidine for the treatment of pseudobulbar affect. Dextromethorphan suppresses the cough reflex by a direct action on the cough center in the medulla of the brain. Levomethorphan is an opioid analgesic of the morphinan family that has never been marketed.

Fenmetozole is an alpha-2 adrenergic receptor antagonist which was developed for the treatment of schizophrenic and/or depressed patients, however never reached the market. It was also shown that the drug may reduce symptoms of minimal brain dysfunction in children and antagonize the effect of barbiturates and ethanol.