SULFACLOZINE is a competitive antagonist of para-aminobenzoic acid (PABA), a precursor of folic acid, in protozoa and bacteria. It is indicated for treatment of coccidiosis in poultry due to infection with Eimeria species, fowl typhoid due to infection with Salmonella gallinarum and fowl cholera due to infection with Pasteurella multocida. Adverse reactions are liver damage, allergic reactions. In poultry undesirable effects, as inappetence, diarrhoea, growth depression, or haemorrhages after administration of sulfaclozine are rare. Prolong use may cause crystal urea.

Diaveridine is an antiprotozoal agent. It inhibits dihydrofolate reductase activity. Diaveridine is genotoxic to mammalian cells in vitro and in vivo. In veterinary it is used for the treatment of coccidiosis. It was reported that EGIS-5645 (considered to be diaveridine) exerts anti-inflammatory properties.

Acetarsone is a pentavalent arsenical compound with antiprotozoal and antihelmintic properties. It was first discovered in 1921 at Pasteur Institute by Ernest Fourneau, and sold under the brand name Stovarsol (fourneau is the French word for stove). Before stovarsol was used in the treatment of congenital syphilis, it had already been used in other diseases : amoebiasis, acquired syphilis, yaws, trypanosomiasis and malaria, and a formidable list of toxic manifestations can be compiled from the literature. Bender (I927) recorded six cases of poisoning with malaise, fever, cedema, jaundice, diarrhoea, albuminuria, bronchitis, coryza and skin troubles, such as diffuse erythema, dryness and pruritus. Of 232 cases of amoebiasis treated by Brown (I935) without a death, thirteen (5.6%) had toxic erythemata, some of them so severe as to amount to exfoliative dermatitis. Although its mechanism of action is not fully known, acetarsone may bind to protein-containing sulfhydryl groups located in the parasite, thereby forming lethal As-S bonds. This may prevent their functioning and eventually kill the parasite.

Nimorazole is an antimicrobial with activity against anaerobic bacteria and protozoa. Its actions and properties are similar to metronidazole. It has also been used in trials studying the treatment of Hypoxia, Radiotherapy, Hypoxic Modification, Gene Profile, Gene Signature, and Head and Neck Squamous Cell Carcinoma, among others. Azanta is developing, nimorazole, as an oral hypoxic radio-sensitiser for the treatment of patients with head and neck cancer who are undergoing radiotherapy. Previously, nimorazole has been approved for use as an anti-protozoal agent and has been launched worldwide. Nimorazole, for the treatment of head and neck cancer patients undergoing radiotherapy received orphan designation by EMA in 2011.

Difetarsone, an anthelmintic drug, was used in the treatment of Trichuris trichiura (whipworm) infestation.

Carnidazole (trade name Spartrix) is an antiprotozoal drug of the nitroimidazole class used in veterinary medicine. Spartrix (Carnidazole) is indicated for oral treatment of trichomoniasis (canker) in ornamental and homing (non-food) pigeons.

Ornidazole is nitroimidazole derivative. It is an antiprotozoal drug that has proven to be effective against Trichomonas vaginalis, Entoamoeba histolytica, Giardia lamblia and Helicobacter pylori. The reduction of the nitro group and the generation of short-lived reactive intermediates are the basis of its parasiticidal activity. Ornidazole is a DNA-tropic drug with selective activity against microorganisms with enzyme systems capable of reducing the nitrogroup and catalyze the interaction between ferrodoxin proteins and nitrocompounds. After the drug penetrates the microbial cell, the mechanism of its action is based reducing the nitrogroup under the influence of the microorganism’s nitroreductases and the activity of the reduced nitroimidazole. The reduction products create compounds with DNA causing it to degrade, and disrupt the DNA replication and transcription processes. Furthermore, the drug’s metabolism products have cytotoxic properties and disrupt cellular respiration processes. It is indicated for the treatment of anaerobic systemic infections caused by ornidazole-sensitive microflora, prevention of infections caused by anaerobic bacteria, during operative treatment (especially middle and straight intestine surgeries), gynecological surgeries, severe intestinal ameobiasis, all extra-intestinal ameobiasis forms, giardiasis. Ornidazole was shown to be effective for the prevention of recurrence of Crohn's disease after ileocolonic resection.

Ipronidazole is an antiprotozoal drug of the nitroimidazole class used in veterinary medicine. Ipronidazole (2-isopropyl-1-methyl-5-nitroimidazole) is used for the treatment of histomoniasis in turkeys and in swine dysentery.

Ronidazole is an antiprotozoal agent. Ronidazole and the other nitroimidazole derivatives damage DNA following reduction of the nitro group. It is used in veterinary for prevention and treatment of various infections including histomoniasis in turkeys, trichomoniasis in pigeons, genital trichomoniasis in cattle, haemorrhagic enteritis in pigs and Tritrichomonas foetus in cats.