Tefludazine (Lu 18-012) is a mixed D2 and 5-HT2 receptor antagonist that was developed as a potential antipsychotic compound. It was shown that tefludazine induced a dose-dependent decrease in both nigra pars compacta (SNC) and ventral tegmental area (VTA) dopamine (DA) activity. The development of the drug was discontinued in Phase I due to toxicological findings in dogs.

Caracemide is a nonspecific inhibitor of macromolecules affecting the synthesis of DNA, RNA, and proteins. Caracemide is an active inhibitor of ribonucleotide reductase as evidenced in the Novikoff tumor model. These inhibitory effects are concentration-dependent with 70 percent of DNA synthesis inhibited by a drug concentration of 1 mkM with a 4 h incubation. However, RNA and protein synthesis inhibition require a concentration of 50-100 mkM. DNA strand breaks were observed only at high in vivo concentrations of 100 mkM. The antineoplastic activity of caracemide was observed in the P388 murine model and in mammary (MX-I) and colon (CX-1) human tumor xenographs implanted in the subrenal capsules of athymic mice. In the MX-1 mammary tumor, a single daily injection provided greater activity than an intermittent schedule. Caracemide was inactive against murine L1210 leukemia, B16 melanoma, Lewis lung carcinoma, CD8FI mammary carcinoma and Colon 38. The toxicity on phase I studies was frequent but generally mild. Of note, significant central nervous system dysfunction manifested by lethargy, depression, and confusion occurred in some and was not predictable. In phase I studies Caracemide failed to demonstrate efficacy in patients with advanced renal cell cancer and advanced large bowel cancer.

Nidroxyzone (Furadroxyl) is an antibacterial agent. It was used for the treatment of experimental trypanosomiasis in laboratory animals.

Olcegepant is a potent and selective CGRP (Calcitonin gene-related peptide) antagonist. The drug was tested in phase II clinical trial, in patients with a migraine, however, the development was terminated.

Piridoxilate is a conjugation product of pyridoxine and glyoxylic acid in which pyridoxine is supposed to facilitate in vivo transformation of glyoxylic acid to glycine rather than to oxalic acid. The protective action of piridoxilate against hypoxia and metabolic inhibition of the myocardium was confirmed in the experiments on the canine heart-lung preparation using the redox potential of the myocardium and the pyridine nucleotide fluorescence of the heart as indices of cellular energy metabolism. The protective action of piridoxilate against hypoxia which may be attributable to rearrangement of the myocardial metabolism. Piridoxilate did not induce any significant changes in objective and subjective sleep variables. Long-term treatment with piridoxilate may result in overproduction of oxalic acid and in calcium oxalate nephrolithiasis. Piridoxilate should be added to the list of chemicals responsible for chronic oxalate nephropathy.

Bitoscanate is a tasteless, odorless, colorless, needle-like crystalline solid material prepared from mustard powder acid and used as an anthelmintic against nematodes, especially hookworms (Necator sp.) and Ancylostoma duodenale. Side effects reported with therapeutic use have been nausea, vomiting, diarrhea, abdominal pain or discomfort, loss of appetite, dizziness or giddiness, vertigo, weakness, headache, and an itching sensation over the body. Such side effects have most often been mild and required no treatment. Bitoscanate is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.

Peliglitazar (also known as BMS 426707-01), a dual α/γ peroxisome proliferator-activated receptor agonist, has been studied in phase I/II clinical trial in patients with type 2 diabetes mellitus. However, this study was discontinued.

Clothixamide is a dopamine antagonist. The compound was invented by Pfizer in the 1960s and is claimed to be useful for the chemotherapy of mental diseases and especially for the control of excited states. Also, clothixamide is claimed to have potent antiemetic properties.