Proxorphan is a N-substituted 6-oxamorphinane patented by American pharmaceutical company Bristol-Myers Co. as opioid analgesic and antitussive drug. Proxorphan acts as a κ-opioid receptor partial agonist and to a lesser extent as a μ-opioid receptor partial agonist.

Suproclone is a sedative and anxiolytic drug in the cyclopyrrolone family of drugs, developed by the French pharmaceutical company Rhône-Poulenc. The mechanism of action by which Suproclone produces it's sedative and anxiolytic effects is by modulating GABAA receptors

Tesicam is a dioxoisoquinoline derivative patented by Pfizer, Chas. and Co., Inc. as an anti-inflammatory agent. In preclinical models, Tesicam shows potent anti-inflammatory activity against carrageenin-induced edema in rats.

Tioperidone is tranquilizer. This antidepressant agent reverses P-glycoprotein-mediated multidrug resistance.

Triflubazam is a 1,5-benzodiazepine derivative. The hypnotic activity of the 1,5-benzodiazepines is limited, and that this is particularly so in the case of triflubazam. Subjects reported impaired sleep with triflubazam (40 mg), and a sense of less wakefulness the morning. The effect of triflubazam may have persisted beyond the night of ingestion. No effect of triflubazam was observed on total sleep time, stage shifts in the first 6 h or latency to the first rapid eye movement period of sleep. Triflubazam has psychopharmacological properties in animals suggestive of antianxiety activity of a longer duration than that of diazepam. The metabolism of triflubazam by man is characterized by extensive N-demethylation, aromatic hydroxylation, aromatic O-methylation and dihydrodiol formation.

Tropanserin (MDL 72422) is a potent and selective 5-HT3 receptor antagonist. It was investigated as a drug for the treatment of migraine. MDL 72222 was shown to be an effective antimigraine agent in a double-blind placebo-controlled study.

Trebenzomine (CI-686) is a centrally acting psychotropic drug structurally distinct from currently available drugs. Preclinical studies indicate that trebenzomine, unlike most psychotropic drugs, has both neuroleptic and stimulant profiles. Stimulant properties of trebenzomine include potentiation of methamphetamine-induced self-stimulation. Neuroleptic properties of trebenzomine include reduction of septal hyperirritability, suppression of conditioned avoidance behavior, blockade of apomorphine-induced emesis in dogs, and elevation of brain homovanillic acid (HVA). Trebenzomine's effect on dopamine (DA) metabolism appears to be related more to the presynaptic release of DA rather than by blockade of postsynaptic DA receptors. Unique preclinical profile suggests a mechanism of action other than dopamine antagonism which could have implications regarding current thinking on the pathophysiology of schizophrenia.

Thiazesim (also known as ) is a benzothiazepine derivative patented by Olin Mathieson Chemical Corp. as an oral anti-depressant and tranquilizer useful in the treatment of Parkinsonism. Thiazesim is chemically related to the tranquilizing drugs chlordiazepoxide and diazepam but possesses a unique action on the limbic system, namely a selective depression of the lateral amygdaloid nucleus in experimental animals. Thiazesim shows potent anti-depressant activity in clinical trials.

Zonampanel (also known as YM872) was developed as selective, potent and highly water-soluble competitive alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptor antagonist. Zonampanel possesses the neuroprotective effect against focal cerebral ischemia and participated in phase II clinical trials in acute stroke patients. However, because of the severe effects, including hallucinations, agitation, and catatonia the further studied were terminated.