Fananserin is a potential antipsychotic compound with a high affinity for both D4 and 5-HT2A receptors, and negligible affinity for D2 receptors. Fananserin has been researched for the treatment of schizophrenia. Fananserin was the first selective D4/5-HT2A antagonist to undergo clinical trials for schizophrenia. It has a high affinity for D4 (Ki 2.9 nM) and 5-HT2A (Ki 0.37 nM) receptors and is over 100-fold selective versus H1, a1 adrenergic, 5-HT1A and D2 dopamine receptors. Development of this compound was halted following phase II clinical trials due to lack of efficacy.

Medorinone is an inhibitor of cAMP phosphodiesterase activity. Inhibition of cAMP phosphodiesterase by medorinone in cardiac and vascular smooth muscle is a mechanism by which this agent produces both positive cardiac inotropy and vascular smooth muscle relaxation. It inhibits platelet aggregation.

FENGABINE, a benzylidene derivative, is a GABAmimetic compound with clinically proven antidepressant action. It inhibits neither monoamine uptake nor monoamine oxidase. It also lacks any sedative effect.

ISBOGREL is a specific thromboxane A2 synthetase inhibitor. Its clinical development was discontinued, although it was a suitable candidate for clinical trials in cardiovascular diseases in which imbalance between thromboxane and prostacyclin may be involved in the pathogenesis.

K-134, a 2(1H)-quinolinone derivative, is a phosphodiesterase 3 inhibitor. It has both anti-thrombotic and anti-hyperplastic activities. It was evaluated in a phase II trial in patients with peripheral artery disease and claudication.