Acetryptine is an antihypertensive agent. Acetryptine was found to bind 5-HT1A and 5-HT1D receptors with high affinity. It may also act as a monoamine oxidase inhibitor (MAOI), specifically, as an inhibitor of MAO-A.

Piboserod (SB 207266) is a selective 5-HT(4) receptor, antagonist. The 5-HT4 receptor antagonists are thought to antagonize both the ability of serotonin to sensitize the peristaltic reflex and 5-HT-induced defecation, at least in animal studies. As 5-HT4 receptors are present in human atrial cells and when stimulated may cause atrial arrhythmias, piboserod was under investigation in clinical trials for atrial fibrillation. In addition, GlaxoSmithKline studied the drug for the management of irritable bowel syndrome. Nevertheless, development both indications had been discontinued. Piboserod has successfully passed phase II clinical trials for the treatment of patients with congestive heart failure.

Cintazone is a non-steroidal anti-inflammatory drug. It is was discovered in the 1960s, and was shown to be an anti-phlogistic agent in animal studies. Clinical development of this drug is not reported.

Marizomib is a natural beta-lactone produced by the marine bacterium Salinispora tropica. Marizomib has a broad inhibition profile for the 20S proteasome and has been shown to inhibit the CT-L (beta5) CT-T-laspase-like (C-L, beta1) and trypsin-like (T-L, beta2) activities of the 20S proteasome. The drug is being tested in phase II clinical trials for the treatment of Multiple Myeloma and Malignant Glioma and in phase I in patients with Non-small Cell Lung Cancer, Pancreatic Cancer, Melanoma or Lymphoma

Azabyperone was developed as tranquilizer and neuroleptic and has never been marketed.

Olpimedone was developed as an anti-rheumatic agent and analgesic, however, the drug that has never been marketed. Information about the current use of olpimedone is not available.

Ocinaplon is anxiolytic in rodents and primates, including humans, with a magnitude of effect comparable to benzodiazepines. It was evaluated to treat Generalised anxiety disorder. The mechanism of action by which ocinaplon produces its anxiolytic effects is by allosteric modulating of GABA-A receptors. The serious adverse event detected in the ocinaplon group was icterus following transaminase elevations. Due to liver complications that occurred in Phase III, development of ocinaplon is discontinued.

Panadiplon (previously known as U-78875) was investigated as a compound with a high affinity for the benzodiazepine receptors. It was studied as a unique anxiolytic agent with a minimum of central nervous system depression for the treatment of anxiety disorders. However, panadiplon was dropped from clinical development due to unexpected hepatic toxicity in human volunteers. It was shown that the drug-induced mitochondrial dysfunction in the liver, and suggested that this dysfunction could be attributed to the carboxylic acid metabolite.