Closantel is a synthetic anti parasitic agent which is highly effective against adults and larvae (6 to weeks old) of liver flukes (Fasciola hepatica), and against several important gastrointestinal roundworms (e.g. Bunostomum, Haemonchus, Oesophagostomum, Ostertagia - Teladorsagia, Strongyloides, Trichostrongylus), as well as against screwworms (maggots of Cochliomyia spp and Chrysomya spp), sheep nasal bots (Oestrus ovis), and sheep keds (Melophagus ovinus). The molecular mode of action closantel is not completely elucidated, but closantel decouples the mitochondrial oxidative phosphorylation, which leads to the inhibition of ATP synthesis, this seems to occur through suppression of the activity of succinate dehydrogenase and fumarate reductase, two enzymes involved in this process. Finally this all cause the death of the parasite. Recently it has been discovered that closantel also inhibits chitinase in Onchocerca volvulus, a filarial nematode causing river blindness in humans. Chitinase is an enzyme involved in larval molting. Its inhibition interrupts their development to adult worms. This drug possesses some side effects: hyper acute anaphylactic reactions in cattle; hypersensitivity reactions; overdoses can cause reduced visibility or blindness, anorexia, lack of coordination and general weakness.

2,4,5-Trichlorophenol is a grey flake or needle-shaped solid. It is used as an intermediate in the manufacture of the herbicide 2,4,5-Trichlorophenoxyacetic Acid (2,4,5-T) and as a fungicide and bactericide. 2,4,5-trichlorophenol (triclofenol piperazine, Ranestol) is an antifungal agent, which was also used against light hookworm infections. Thirty persons who were positive for hookworm eggs in their stools were treated with 50 mg/kg of triclofenol piperazine dissolved in 5 per cent polyethylene glycol Ranestol® in soft gelatin capsules. Nineteen of these showed 77 to 100 % reduction in egg count average when compared with the pre-treatment counts. Side reactions were limited to mild and transient nausea in 23, vomiting in 7, transient abdominal cramps and headache in 2 each. 2,4,5-trichlorophenol complexed with dicyclohexylamine was used for treatment of experimental mycosis. From the mycological and clinical evaluation the conclusion can be drawn that the effect of phenol in lipophilic ointment is comparable to that of clotrimazole.

Enpiroline (WR 180,409) is an antimalarial compound. It demonstrates activity against Plasmodium falciparum both in vitro and in non-immune infected subjects. Additionally, it exerts antischistosomal activity.

Pafuramidine or DB289, [2,5-bis-(4-amidinophenyl)furan bis-O-methylamidoxime] is a pro-drug of DB75, [2,5-bis(4-amidinophenyl)furan] also known as furamidine. The biotransformation process of DB289 to DB75 in the human liver consists of three O-demethylation reactions catalyzed by the Cyp4F enzyme subfamily and three N-dehydroxylation reactions catalyzed by cytrochrome b5 and NADH-cytochrome b5 reductase. DB289 was studied for therapeutic treatment against human African trypanosomiasis, Pneumocystis pneumonia and malaria. In November 2006, Immtech Pharmaceuticals, Inc. announced that the U.S. Food and Drug Administration (FDA) had granted orphan drug designation for pafuramidine (DB289) to treat Pneumocystis jiroveci pneumonia (PCP), a common life-threatening opportunistic infection in HIV/AIDS and other immunosuppressed patients. Despite the high efficacy of DB289 in patients, the mechanism of action of DB75 is unknown. The mechanism of antimicrobial activity of diamidine compounds is incompletely understood. They undergo active uptake by purine transporter systems in trypanosomes and their mechanism of action may involve interference with DNA-associated enzymes inhibition of heme crystallization11 or/and collapse of the transmitochondrial membrane potential.

FENIODIUM is an anthelmintic agent.

Thiacetarsamide is a drug containing trivalent arsenic. In the USA it was used for the treatment of Heartworm Infection in dogs and cats under tradename Caparsolate, however, it was discontinued because of the availability of safer alternatives. The mechanism of action for thiacetarsamide is modulation of glucose uptake and metabolism; inhibition of glutathione reductase, and alteration of the structure and function of the surface of the intestinal epithelium of the parasites.

Carbantel is imidoylurea derivative patented by pharmaceutical company Sterling Drug Inc. As anthelmintic agent.

Albitiazolium (SAR97276) is a clinical antimalarial candidate from a series of choline analogs designed to inhibit plasmodial phospholipid metabolism. Albitiazolium exerts powerful in vitro and in vivo antimalarial activities. Albitiazolium has been shown to have appropriate pharmacokinetic and safety parameters in humans and it was being tested in phase II clinical trials by Sanofi, with confirmed antimalarial activity in adult patients. However, Sanofi discontinued development of Albitiazolium.

Nitramisole, an imidazothiazole derivative, is an anthelmintic. Nitramisole was effective against migrating Strongylus vulgaris larvae in ponies. Treatment of infected ponies with Nitramisole resulted both a clinical and radical cure.

ISOMETAMIDIUM (as a chloride salt) is widely used in tropical countries as an antiprotozoal agent to control animal trypanosomiasis. It is used principally in cattle but also in sheep, goats, buffalos, donkeys, horses, camels and dogs.