Entacapone is a selective and reversible inhibitor of catechol-O-methyltransferase (COMT), that in combination with carbidopa and levodopa used for the treatment of Parkinson's disease. Physiological substrates of COMT include DOPA, catecholamines (dopamine, norepinephrine, and epinephrine) and their hydroxylated metabolites. The function of COMT is the elimination of biologically active catechols and some other hydroxylated metabolites. When decarboxylation of levodopa is prevented by carbidopa, COMT becomes the major metabolizing enzyme for levodopa, catalyzing its metabolism to 3-methoxy-4-hydroxy-L-phenylalanine (3-OMD). When entacapone is given in conjunction with levodopa and carbidopa, plasma levels of levodopa are greater and more sustained than after administration of levodopa and carbidopa alone. It is believed that at a given frequency of levodopa administration, these more sustained plasma levels of levodopa result in more constant dopaminergic stimulation in the brain, leading to greater effects on the signs and symptoms of Parkinson’s disease. The higher levodopa levels may also lead to increased levodopa adverse effects, sometimes requiring a decrease in the dose of levodopa. When 200 mg entacapone is coadministered with levodopa/carbidopa, it increases levodopa plasma exposure (AUC) by 35-40% and prolongs its elimination half-life in Parkinson’s disease patients from 1.3 to 2.4 hours. Plasma levels of the major COMT-mediated dopamine metabolite, 3-methoxy-4-hydroxy-L-phenylalanine (3-OMD), are also markedly decreased proportionally with increasing dose of entacapone. In animals, while entacapone enters the CNS to a minimal extent, it has been shown to inhibit central COMT activity. In humans, entacapone inhibits the COMT enzyme in peripheral tissues. The effects of entacapone on central COMT activity in humans have not been studied.

Nimustine is one of nitrosoureas used in the treatment of cancer. Nimustine alkylates and crosslinks DNA, thereby causing DNA fragmentation, inhibition of protein synthesis, and cell death. It is used in the treatment of brain tumor (in particular, high-grade gliomas), gastrointestinal cancers (stomach cancer, liver cancer, colorectal cancer), lung cancer, malignant lymphoma, chronic leukemia. Nimustine side effects are: leukopenia, thrombocytopenia, hypoproteinemia, anemia, Increased bleeding, proteinuria, interstitial pneumonia, anorexia, stomatitis, nausea, vomiting, general weakness, fever, headache, dizziness, seizures, alopecia, allergic reactions (rash).

Mebezonium is a component of T-61/Tanax (a combination of embutramide, mebezonium iodide, tetracaine hydrochloride), a product which is indicated for euthanasia in animals. The drug was withdrawn from the market by the manufacturer's decision.

Cyphenothrin is one of the type II pyrethroid insecticide, in combination with fipronil it used to provide dogs with protection to common topical parasites in dogs. Cyphenothrin primarily affects sodium channels in excitable membranes causing a prolongation of the sodium current during excitation. The prolonged sodium current results in the development of a depolarizing after potential following the action and is responsible for the induction of repetitive activity, which is the most characteristic effect of pyrethroid poisoning in the nervous system. At low concentrations, insects and other arthropods suffer from hyperactivity. At high concentrations, they are paralyzed and die.

Methylephedrine is one of the ephedra alkaloids that is found in varying amounts in different species of the plant genus Ephedra. Methylephedrine is a popular antitussive, bronchodilator, analgesic, antipyretic, and widely used mixed with other drugs in preparations for treatment of the common cold. N-Methylephedrine, its salts, optical isomers, and salts of optical isomers are in FDA list of Exempt chemical mixtures.

Piflufolastat F 18 (PYLARIFY®) is an 18F-labelled diagnostic imaging agent that has been developed by Progenics Pharmaceuticals Inc., a Lantheus company, for positron emission tomography (PET) that targets prostate-specific membrane antigen (PSMA). Piflufolastat F 18 binds to cells that express PSMA, including malignant prostate cancer cells, which usually overexpress PSMA. Fluorine-18 (F 18) is a β emitting radionuclide that enables positron emission tomography. Piflufolastat F 18 was approved in the USA on 27 May 2021 for PET of PSMA positive lesions in men with prostate cancer with suspected metastasis who are candidates for initial definitive therapy or with suspected recurrence based on elevated serum prostate specific antigen (PSA) level.

Hydroprene is a synthetic version of the insect hormone that regulates growth and development. Hydroprene can be considered as an alternative to conventional insecticides because of its specific activity against immature insect stages, low persistence in the environment, and virtually non-toxic effects on mammals. Hydroprene products are used on a variety of indoor sites including homes, offices, warehouses, restaurants, hospitals, and greenhouses.

Pirarubicin is a new kind of anthracene nucleus broad-spectrum antitumor antibiotic. This compound was rapidly incorporated into tumor cells, inhibiting DNA polymerase alpha, DNA topoisomerase II and subsequently DNA synthesis. Inhibition of RNA synthesis was also noted. It is indicated as an antineoplastic agent for the treatment of the following diseases: head and neck cancer, breast cancer, gastric cancer, urothelial cancer, ovarian cancer, uterine cancer, acute leukemia, malignant lymphoma. Among the side effects, cardiac toxicity, alopecia and disturbance of the digestive organs were mild.

Propoxur (Baygon) is a carbamate insecticide that has recently attracted considerable attention as a possible treatment option for addressing the bedbug epidemic. Propoxur is a non-systemic insecticide with a fast knockdown and long residual effect used against the turf, forestry, and household pests and fleas. The generally accepted mechanism of toxicity for propoxur involves the inhibition of cholinesterase. Propoxur is also used in pest control for other domestic animals, Anopheles mosquitoes, ants, gypsy moths, and other agricultural pests. It can also be used as a molluscicide. Several U.S. states have petitioned the Environmental Protection Agency (EPA) to use propoxur against bedbug infestations, but the EPA has been reluctant to approve indoor use because of its potential toxicity to children after chronic exposure.

Cyphenothrin, (+)-trans- (d,d,trans-cyphenothrin) is the type II pyrethroid insecticide, acting by contact poisoning Cyphenothrin, (+)-trans- is used in public health against flies, mosquitoes, cockroaches, etc. Cyphenothrin is the ISO common name for a racemic mixture of 4 pairs of diastereoisomers, designated as (±)-α-cyano-3- phenoxybenzyl (±)-cis-trans- chrysanthemate. The name Cyphenothrin, (+)-trans- refers to an enantio-enriched mixture, comprised mainly of the single stereoisomer (S)-α-cyano-3- phenoxybenzyl (1R, 3R)-2,2-dimethyl-3-(2-methylprop-1-enyl) cyclopropanecarboxylate, with only small proportions of the other stereoisomers, as defined by the WHO specification. Cyphenothrin, (+)-trans- is almost insoluble in water but highly soluble in organic solvents, such as hexane, ethanol, acetone, toluene etc. Cyphenothrin, (+)-trans- stable under normal storage conditions but is readily hydrolyzed in water at higher pH and is sensitive to light. Cyphenothrin, (+)-trans- has a low potential for bioaccumulation due to hydrolysis, photolysis and metabolism in water, soil and in biota. The data for toxicology of Cyphenothrin, (+)-trans- partly rely on studies conducted with cyphenothrin. Cyphenothrin, (+)-trans- generally shows low mammalian toxicity and is not a sensitizer in the Buehler and is not irritating to the rabbit eye and skin. There was no evidence of carcinogenicity in the rat or mouse. There was no evidence of mutagenic responses in bacterial, micronucleus or sister chromatid exchange tests. In a 2-generation reproduction study in the rat, no reproductive effects were observed at any dose level. There was no evidence of teratogenicity or developmental effects in rats or rabbits, although there was a decrease in maternal weight gain and a consequential decrease in rat offspring viability at the high dose tested. Cyphenothrin, (+)-trans- is very toxic to Daphnia magna and fish but it has a low toxicity to bobwhite quails. On the basis of the one-year dog study, a NOEL of 16.8 to 19.6 mg/kg bw/d is established by the Swiss Office of Public Health. The Cyphenothrin, (+)-trans- TC was classified as moderately toxic (Class 3) in Switzerland and, although it has not been classified by the International Programme on Chemical Safety (IPCS), this organization has classified the closely related cyphenothrin (1R-isomers) as Class II, moderately hazardous.