Besonprodil (also known as CI-1041), an NR2B subunit specific NMDA receptor antagonist, has been developed for the treatment of certain inflammatory and neuropathic pain, however, these studies were discontinued. Besides, besonprodil was investigated as a supplemental medication for Parkinson's disease. Experiments on animals have shown that this drug could be effective in counteracting the dyskinesia associated with long-term treatment with levodopa and related drugs.

Siratiazem [LRA 113] is a calcium channel antagonist that is structurally similar to diltiazem but has a branched alkyl group on the basic nitrogen. Siratiazem has been developed in an attempt to limit the in vivo N-demethylation that is known to occur with diltiazem. Preliminary binding and functional studies in cardiac and vascular tissues indicate that it not only binds to diltiazem binding sites but also exhibits Ca2+ channel blocking properties comparable to diltiazem. Siratiazem has a similar profile of activity to its parent compound, diltiazem, in that it blocks calcium channels in vascular, intestinal smooth muscle and cardiac tissue, and is least potent in cardiac muscle. At higher concentrations, siratiazem may also block cardiac sodium channels.

Modipafant is a dihydropyridine derivative patented by American multinational pharmaceutical corporation Pfizer Ltd. as platelet-activating factor antagonist for bronchoconstriction and asthma treatment. Platelet-activating factor, proposed as an important inflammatory mediator in asthma, reproduces several of the features of asthma, such as microvascular leakage, mucus secretion, bronchoconstriction, and possibly increased airway responsiveness. Unfortunately, in clinical trials, Modipafant failed to demonstrate superior efficacy compared to placebo.

Vadimezan (5,6-dimethyl(xanthenone-4-acetic acid), ASA404, DMXAA) is a fused tricyclic analogue of flavone acetic acid with potential antineoplastic activity. In pre-clinical mouse tumour models it was demonstrated that administration of Vadimezan rapidly leads to disruption of the existing vasculature in the tumour and consequent haemorrhagic necrosis of the tumour. This was consistent with the finding that a single dose of Vadimezan induced a prolonged reduction in the growth of xenografted tumours in animal models. The ability to disrupt the vasculature in these pre-clinical models has been attributed to a rapid induction of cytokines, particularly TNFα (tumour necrosis factor α), serotonin and nitric oxide, resulting in hemorrhagic necrosis and a decrease in angiogenesis. Despite the fact that the molecular targets for the drug remained unknown, the promising pre-clinical results led to Vadimezan being selected for clinical development. Results of Phase I trials showed some restriction of tumour blood flow within 24 h of treatment, although this was not as dramatic as seen in pre-clinical models. Unlike the animal models, there was also very little evidence for the rapid death of blood vessels or for increases in TNFα levels in human tumors. No difference in antitumour activity, cytokine induction or toxicity was observed between two parallel Phase I trials, one dosed weekly and the other dosed every 3 weeks. Therefore the drug proceeded to Phase II clinical trials, dosed every 21 days in combination with chemotherapeutic agents. These trials indicated the drug had small benefits in the treatment of non-small-cell lung cancer and prostate cancer. However, a subsequent Phase III clinical trial was not able to reproduce this response and clinical development was halted.

Metiprenaline was developed as a bronchodilator. Information about the current use of this compound is not available.

Lucimycin (lucensomycin or etruscomycin) is a polyene antibiotic with antimycotic activity. Originally it was isolated from Streptomyces lucensis n. sp.

Fosbretabulin (Combretastatin A4 phosphate, CA4P) is the lead compound of a relatively new class of agents termed vascular disrupting agents that target existing tumor blood vessels. Rapid tumor blood flow shutdown has been demonstrated in preclinical models and patients by various techniques such as dynamic contrast-enhanced MRI, perfusion computed tomography and PET scans following CA4P infusion. CA4P typically induces rapid tumor necrosis in the center of the tumor and leaves a rim of viable cells in the periphery. In oncology, CA4P does not appear to be that active by itself, but may be more efficacious when combined with chemotherapy, antiangiogenic therapy and radiation therapy. Combretastatin was initially isolated from the root bark of the South African Bush willow Combretum caffrum in 1982 by Pettit and colleagues at the Arizona State University (AZ, USA). Combretastatin A4 phosphate binds avidly to tubulin at the colchicine-binding site to inhibit microtubule assembly and destabilize the cytoskeleton. CA4P is a tubulin-binding agent that binds at or near the colchicine binding site of β-tubulin (Kd = 0.40 uM), inhibits tubulin assembly with IC50 of 2.4 uM. Fosbretabulin has orphan drug status in the EU and the US for the treatment of ATC (Anaplastic Thyroid Cancer). Later the development of this drug was discontinued.

Pirdonium is an antihistamine agent. It is the hydrophilic Histamine H1 receptor antagonist.

Piroxantrone is one of a series of compounds commonly known as anthrapyrazoles developed in an effort to combine the broad antitumor activity of the anthracyclines with decreased myocardial toxicity. The mechanism of action of piroxantrone and other anthrapyrazoles is incompletely understood but likely involves DNA binding with induction of DNA strand breaks, DNA-protein cross-linking, and inhibition of DNA, RNA, and protein synthesis. Collectively, these findings suggested an interaction with topoisomerase II. Piroxantrone demonstrated antitumor activity in a wide spectrum of experimental systems against breast carcinoma, colon carcinoma, sarcoma, melanoma and leukemia. Piroxantrone is inactive in patients with persistent, progressive, or recurrent ovarian cancer who recently had received a platinum-based regimen. Piroxantrone has detectable but minimal activity against disseminated malignant melanoma. A phase II clinical trial of the piroxantrone administration for the treatment of advanced metastatic or recurrent endometrial cancer was prematurely terminated due to lack of patient accrual.

Pinoxepin belongs to the dibenzoxepine series of drugs which are characterized by a 6-7-6 tricyclic nuclear structure. Clinical studies indicated that pinoxepin was a potent antipsychotic-sedative equally effective to chlorpromazine and thioridazine. Pinoxepin in studies with chronic schizophrenic patients displayed useful effects on behavior without unduly prominent side effects. In doses above 300 mg seizures are reported and more frequent changes in liver-function tests were noted than with standard drug, but below 300 mg pinoxepin was found to have side effects similar to chlorpromazine and marked sedative effects.