Rolicyclidine (PCPy) is a dissociative anesthetic agent that has hallucinergic and sedative properties. In rats, it produces stimulant effects like that of PCP (hydrochloride) and was therefore added to the Schedule I list of illegal drugs in the USA. It is thought to be much less stimulating than PCP however, and more similar to opioids, or other central nervous system depressants.

Nifursemizone, a 5-nitrofuran derivative, is an antiprotozoal drug. It is used in the treatment of histomoniasis in poultry.

The benzisoxazolyl piperidine derivative and atypical antipsychotic abaperidone [FI 8602] is being developed by Ferrer for the treatment of schizophrenia. Abaperidone is a potent antagonist of 5-HT2A receptor and dopamine D2 receptor with IC50s of 6.2 and 17 nM.

Ciluprevir (BILN-2061) is a selective inhibitor of the HCV NS3 serine protease, which was developed by Boehringer Ingelheim for the treatment of hepatitis C infection. The drug was discontinued in phase II due to adverse events such as cardiac toxicity (demonstrated in animals). In the cell-based replicon assay, ciluprevir inhibited HCV RNA replication at low nanomolar levels. It had inhibitory rate constant (Ki) values of 0.3 and 0.66 nM for the NS3 proteases of HCV genotypes 1a and -1b, respectively.

Cipralisant (GT-2331) is an H3-receptor ligand developed by Gliatech in the late 1990s. The drug exhibits complex pharmacology: it behaves as an antagonist in a guinea pig jejunum contraction assay and mouse disogenia model, as a partial agonist in a rat brain synaptosome model, and as a full agonist at recombinant H3 receptors. In preclinical models, cipralisant enhanced wakefulness and improved learning in developmental rat models. In 2000 cipralisant was investigated in the clinical trials for the treatment of attention-deficit hyperactivity disorder, but due to the bankruptcy of Gliatech the development of the drug was discontinued.

GSK-163090 is potent, selective, and orally active 5-HT1A/B/D receptor antagonist. GSK163090 was found to combine potent in vivo activity with a strong preclinical developability profile, and on this basis it was selected as a drug candidate with the aim of assessing its potential as a fast-onset antidepressant/anxiolytic. GSK-163090 had been in phase II clinical trials by GlaxoSmithKline for the treatment of major depressive disorder (MDD) and anxiety disorders. However, this research has been discontinued.

Dinazafone exhibits anticonvulsant, anxiolytic and myorelaxant effects. Diazepam and N-desmethyl-diazepam formed after dinazafone certainly contributed to its antileptazol effect.

Diphoxazide is the anticonvulsant and psychosedative agent.

Diprafenone closely resembles propafenone in both structure and function. It is beta adrenoceptor antagonists and sodium channel antagonists. Diprafenone is highly protein bound in plasma. It has demonstrated efficacy against supraventricular and ventricular arrhythmias in clinical trials. Diprafenone produced first-degree atrioventricular block in 6/20 patients tested with coronary artery disease and sustained ventricular tachycardia. Intravenous application of diprafenone significantly increased atrioventricular nodal conduction time as well as the effective refractory periods of the right ventricle and the accessory pathway in both the antegrade and retrograde directions in 15 patients with the Wolff-Parkinson-White syndrome and symptomatic supraventricular tachycardia.