Pentaerythritol tetranitrate is an organic nitrate that has been used for the treatment of angina pectoris. Upon administration, the drug undergoes exstensive metabolism to NO which causes vasodilation and the relaxation of smooth muscle cells. The compound belongs to a familiy of explosive substances and may be used accordingly.

Thiorphan is the first potent synthetic inhibitor of enkephalinase. Thiorphan displays antinociceptive activity after systemic administration. Thiorphan also inhibits to a lesser extent the widely distributed angiotensin-converting enzyme, a carboxydipeptidase implicated in blood pressure regulation. Thiorphan failed to potentiate allergen-induced airway responses in asthma. Thiorphan significantly reduced the castor oil-induced diarrhea in rats when administered intravenously but not when administered intracerebroventricularly. Racecadotril, via its active metabolite thiorphan, was consistently effective in animal models and patients with various forms of acute diarrhea by inhibiting pathologic (but not basal) secretion from the gut without changing gastro-intestinal transit time or motility.

Omecamtiv mecarbil (CK-1827452) is a specific cardiac myosin activator and a clinical drug for left ventricular systolic heart failure (in Phase 2 of development). Omecamtiv mecarbil is an inotropic agent that prolongs systolic ejection time and increases ejection fraction through myosin ATPase activation.

Sulrnazole (the former AR-L 115 BS) is a benzimidazole derivative with positive inotropic, positive chronotropic and vasodilator effects. Sulrnazole also has been shown to improve cardiac index and reduce pulmonary capillary wedge pressure without significant change in heart rate or arterial pressure. Intravenous administration caused a 217 per cent increase in cardiac output with a 25 per cent decrease in pulmonary wedge pressure. Short-term oral administration resulted in a 317 per cent increase in cardiac index and a 317 per cent increase in ejection fraction. Side effects have included visual blurring and transient colour blindness. Sulmazol has been demonstrated to improve regional wall motion in patients with ischemic heart disease and to abolish pacing-induced ischemia. Sulrnazole is an A1 adenosine receptor antagonist. It is also a phosphodiesterase inhibitor.

Kynurenine is a metabolite of the amino acid L-tryptophan used in the production of niacin. Kynurenine is synthesized by the enzyme tryptophan dioxygenase, which is made primarily but not exclusively in the liver, and indoleamine 2,3-dioxygenase, which is made in many tissues in response to immune activation. Kynurenine and its further breakdown products carry out diverse biological functions, including dilating blood vessels during inflammation and regulating the immune response. Evidence suggests that increased kynurenine production may precipitate depressive symptoms associated with interferon treatment for hepatitis C. Cognitive deficits in schizophrenia are associated with imbalances in the enzymes that break down kynurenine. Kynurenine production is increased in Alzheimer's disease and cardiovascular disease where its metabolites are associated with cognitive deficits and depressive symptoms.

Tetradecylthioacetic acid (TTA) is a hypolipidemic antioxidant with immunomodulating properties involving activation of peroxisome proliferator-activated receptors (PPARs). TTA exerts both hypolipidemic and anti-inflammatory effects in psoriasis patients - TTA can be of therapeutic benefit for a subgroup of psoriatic patients. TTA may improve myocardial function in heart failure, potentially involving its ability to decrease the availability of free fatty acids in plasma and increase the myocardial proportion of n-3 polyunsaturated fatty acids. TTA attenuates dyslipidemia in patients with type 2 diabetes mellitus. These effects may occur through mechanisms involving PPAR-alpha and PPAR-delta activation, resulting in increased mitochondrial fatty acid oxidation.

Zibotentan (ZD4054) is a potent and specific orally available endothelin A (ETA) receptor antagonist, with no measurable affinity for endothelin B receptor. Activation of the ETA receptor by ET-1 has emerged as an important factor promoting tumor cell proliferation, survival, angiogenesis, migration, invasion, and metastasis in several tumor types. Zibotentan inhibits endothelin-mediated mechanisms that promote tumour cell proliferation. Zibotentan was being developed by AstraZeneca as treatment for heart failure, hormone resistant prostate cancer and other cancers including non-small cell lung, ovarian and breast cancer. However, following disappointing results from a phase III trial in patients with advanced prostate cancer, AstraZeneca decided to discontinue the development of zibotentan as a potential treatment for cancer. AstraZeneca undertook preclinical studies in the UK with zibotentan to investigate its potential as a treatment for heart failure. However, development for this indication has been discontinued.

Carmoxirole is a dopamine D2 receptor agonist with limited central activity that modulates sympathetic activation and subsequently reduces pre-load and afterload in animals. It was shown, that carmoxirole induced beneficial effects on hemodynamic and neurohumoral parameters in heart failure. In addition, experimental evidence showed that carmoxirole lowered blood pressure in various models of hypertension mainly or exclusively through inhibition of noradrenaline release from sympathetic nerve endings. That effect of carmoxirole was mediated by presynaptic dopamine receptors with the characteristic that release inhibition was restricted to low rates of sympathetic nerve discharge.

Piboserod (SB 207266) is a selective 5-HT(4) receptor, antagonist. The 5-HT4 receptor antagonists are thought to antagonize both the ability of serotonin to sensitize the peristaltic reflex and 5-HT-induced defecation, at least in animal studies. As 5-HT4 receptors are present in human atrial cells and when stimulated may cause atrial arrhythmias, piboserod was under investigation in clinical trials for atrial fibrillation. In addition, GlaxoSmithKline studied the drug for the management of irritable bowel syndrome. Nevertheless, development both indications had been discontinued. Piboserod has successfully passed phase II clinical trials for the treatment of patients with congestive heart failure.

PD123319 is a potent, selective AT2 angiotensin II receptor antagonist with IC50 of 34 nM.PD123319 had been in phase I clinical trials by Pfizer for the treatment of hypertension. However, this research has been discontinued.