Metergotamine (MY-25 or 1-methyl-ergotamine-bitartrate) is a derivative of ergotamine and belongs to peptide alkaloids. It exerts a dampening effect on vessels, in that relaxation is brought about in contracted vessels, whereas contraction is brought in dilated vessels. Metergotamine was being studied in migraine prophylaxis.

Chugai Pharmaceutical is developing a parathyroid 1 receptor agonist called as PCO371. It is known that parathyroid hormone (PTH) is essential for calcium homeostasis and its action is mediated by the PTH type 1 receptor. PCO371 can provide a new treatment option for PTH-related disorders, including hypoparathyroidism. This drug participated in phase I clinical trial in healthy volunteers. However, Chugai Pharmaceutical has terminated this study. No recent reports of the development of PCO371are available.

Guaithylline (or Guaifylline), a xanthine derivative that was studied as a bronchodilator and expectorant, however, has never been marketed.

(E)-Tetrachlorovinphos is an (E)- isomer of Tetrachlorovinphos. Tetrachlorovinphos is an organophosphate cholinesterase inhibitor that is used as an insecticide. Tetrachlorvinphos was introduced and first used commercially in 1966 in the USA. Tetrachlorvinphos was originally registered for use on various food crops, livestock, pet animals. Tetrachlorvinphos is applied dermally to livestock to control flies and mites. It is used as an oral larvicide in cattle, hog, goats and horses; in cattle ear tags to control flies; in cattle feedlots; in poultry dust boxes to control poultry mites; and in poultry houses. Tetrachlorvinphos also is used in pet sleeping areas and pet flea collars and to control flies around refuse sites, recreational areas, and for general outdoor treatment. Tetrachlorvinphos can cause cholinesterase inhibition in humans; that is, it can overstimulate the nervous system causing nausea, dizziness, confusion, and at very high exposures (e.g., accidents or major spills), respiratory paralysis and death. In 2014, the Natural Resources Defense Council (NRDC) filed a lawsuit against the United States Environmental Protection Agency (EPA) seeking EPA to respond to NRDC’s 2009 petition to ban tetrachlorvinphos in common pet flea treatment products. Tetrachlorvinphos is reportedly registered for use in Canada, South Africa, and Australia.

Navitoclax (ABT-263) is an oral selective inhibitor of B-cell leukemia 2 (Bcl-2) family of proteins with potential antineoplastic activity. Navitoclax is a small molecular with the formula of C47H55ClF3N5O6S3 and Molecular Weight of 974. As a Bad-like Bh3 minetic, ABT-263 binds to Bcl-2 family proteins Bcl-2, Bcl-xl and Bcl-w, disrupts the interaction between Bcl-2/Bcl-xl /Bcl-w and pro-apoptotic proteins such as Bim, Bad and Bak, which trigger the caspases-initiated cell death pathway to induce apoptosis. Navitoclax has been in phase II clinical trials by Abbvie for the treatment of prostate cancer, chronic lymphocytic leukaemia and lymphoma. However, this research has been discontinued.

Dimefadane is the indanamine derivative. It was developed as analgesic.

Prodilidine is an arylpyrrolidine derivative patented by Mead Johnson & Co.as moderately potent analgesic. By comparison with other drugs, including morphine, Prodilidine has a prompt and unusually sustained antinociceptive action in rodents by all routes. Prodilidine substantially lacks antipyretic, anti-inflammatory, antitussive, constipating, respiratory depressant, and cardiovascular effects. Prodilidine resembles meperidine in excitatory properties and body-temperature lowering action at high dosage. The d-isomer is about twice as potent and toxic as the l-isomer parenterally; by the gastric route, the difference is markedly less.