Amfonelic acid (AFA) is a dopamine reuptake inhibitor. Experiments on rats have shown that AFA treatment completely prevented the effects of methamphetamine on the dopaminergic system, both morphologically and biochemically.

Fenestrel (ORF-3858) is a nonsteroidal antizygotic compound. It antagonizes progesterone. Fenestrel is a post-coital contraceptive.

Spiromustine is a bifunctional nitrogen alkylating agent with antineoplastic activity and lipophilic properties. Preclinical screening has shown activity against a variety of tumors, including an intracranially implanted ependymoblastoma. Alkylating activity has been demonstrated in an intracerebral glioma in the rat. Spiromustine is a cell cycle non-specific agent. Animal pharmacology studies have shown a biphasic plasma decay curve, with hepatic metabolism and excretion, an enterohepatic circulation of metabolites, and approximately 50% renal excretion of unchanged drug. Toxicology studies in mice, rats, and dogs showed that dose-related myelosuppression and neurotoxicity predominated; other organ toxicities were mild. In Phase I clinical trials Neurotoxicity was the dose-limiting toxicity presenting as alterations in cortical integrative functions (orientation, language, coordination), leading to a decrease in the level of consciousness.

Psilocybin is a naturally occurring psychedelic prodrug compound produced by more than 200 species of mushrooms, collectively known as psilocybin mushrooms. Once ingested, psilocybin is rapidly metabolized to the psilocin, which then acts on serotonin receptors in the brain. Psilocybin was identified as the active hallucinogenic compound in magic mushrooms in 1959, but humans have used assorted psilocybin mushrooms in religious ceremonies since prehistoric times. In the 1960's psilocybin was marketed for use as a treatment for various psychoses, however, it was withdrawn from the market when the regulatory environment changed. Recently there has been as renewed interest in studying the medicinal uses of psilocybin for treatment of anxiety, depression, migraine headaches, addictions, and other neuropsychiatric conditions.

Idalopirdine (Lu AE58054) is a Serotonin 6 receptor (5-HT6) antagonist. Idalopirdine exrets good oral bioavailability and robust efficacy in a rat model of cognitive impairment in schizophrenia. In rats idalopirdine potentiates the effects of acetylcholinesterase inhibitor donepezil on two pharmacodynamic biomarkers associated with cognition, i.e. neuronal oscillations and extracellular ACh levels in the hippocampus. Such potentiation could contribute to the procognitive effects of idalopirdine observed in donepezil-treated Alzheimer's disease patients. The compound is being developed by Lundbeck as an adjunctive therapy with acetylcholinesterase inhibitor donepezil, and is in phase III development for the treatment of Alzheimer's disease in multiple countries worldwide. A phase II trial for the treatment of cognitive impairment associated with schizophrenia was conducted; however no recent reports of development for idalopirdine have been identified.

Ripazepam (CI 683 or pyrazapon) is a pyrazolodiazepine that has anxiolytic effects. It is related to certain benzodiazepines such as zolazepam. In animal studies, it showed anxiolytic effects without sedative or depressant effects. In rats, it did not elicit a tumorigenic potential. Although ripazepam was found significantly superior to placebo and was well tolerated in neurotic patients, it has never been marketed for clinical use.

Disobutamide suppresses ventricular arrhythmias in several in vivo animal models. In particular, disobutamide suppressed ventricular arrhythmias in ouabain-toxic dogs and in dogs in which myocardial infarction. Clear cytoplasmic vacuolation associated with disobutamide is an example of a remarkable morphologic change not associated with apparent overt toxicity based on various functional tests. Clinically in the dog if vacuolation was associated with cell injury, one might expect a chronic debilitating condition as seen in the case of many spontaneous genetic storage diseases. Chronic heart failure or a gastrointestinal motility disorder might occur as a result of the changes in the musculature of coronary arteries or gastrointestinal wall, respectively. Disobutamide, because of its apparent low toxicity, can be recommended as useful for investigations aimed at determining the borderline between physiologic limits and toxicity of intracellular drug storage and for advancing knowledge of mechanisms involved in xenobiotics entry and storage in cells. Disobutamide was withdrawn from clinical testing when clear cytoplasmic vacuoles were found in the rat and dog during toxicity studies. Disobutamide induced vacuoles in all cell types except rat leukaemia. The drug induced cell death and reduction in confluency or cell count in cultures of all cell types except rat carcinoma and rabbit aorta muscle.

Thyromedan is a thyroalkanoic acid derivative with hypocholesterolemic activity. In clinical trials, Thyromedan in daily doses of 8 to 32 mg caused a decrease in serum cholesterol levels. The serum total triglycerides and the α- and β-lipoprotein partition of cholesterol and triglycerides were unaffected.

Iodometomidate I-123, R- (also known as ) is phenylethylimidazole derivative studied as a diagnostic agent for adrenal imaging. Iodometomidate is a highly suitable tracer combining specific uptake in adrenocortical tissue with far lower radiation exposure compared to norcholesterol scintigraphy. Phase III clinical trial for Adrenal Gland Neoplasms imaging is currently ongoing.

Letimide is a new analgesic. It is a cyclic derivative of a salicylamide. The analgesic effect of this drug as determined in rats showed a higher potency than aspirin, but was without anti-inflammatory and antipyretic activity. Letimide is not a genotoxic agent according to the cytogenetic damage observed in vivo and in vitro, and would seem to justify other preclinical and clinical studies to confirm its lack of toxicity. Known adverse effects are headache and dizziness.