ARSTHINOL, an organoarsenical compound, is an antiprotozoal agent used for the treatment of mild or asymptomatic intestinal amebiasis. ARSTHINOL in complex with cyclodextrin displays an anticancer activity.

Glycobiarsol was known under the brand name Milibis. Glycobiarsol is found to be very effective in intestinal infections. Milibis is an antiprotozoal agent that has been used in humans as well as in dogs.

Melarsomine (melarsomine dihydrochloride) is an organic arsenical chemotherapeutic agent and is a trypanocidal antiparasitic drug. As of 2016 DIROBAN, a generic melarsomine dihydrochloride product, is the only FDA-approved treatment for adult heartworm (Dirofilaria immitis) infection in dogs. It is not approved for treatment in cats, or dogs in late-stage infection. It is marketed by Merial under the trade name Immiticide and is not currently available in the U.S. due to a manufacturing shortage. Sponsored by Anzac Animal Health, LLC and distributed by Zoetis, Inc., DIROBAN is a prescription animal drug supplied as a sterile powder that must be reconstituted with an accompanying sterile water diluent. The exact mode of action on D. immitis is unknown. Post-treatment mortality due to thromboembolism and/or progression of the underlying disease may occur in 10 to 20% of the Class 3 patients treated with DIROBAN.

Melarsoprol is an organoarsenic compound that was used for the treatment of sleeping sickness (African trypanosomiasis) since 1949. Melarsoprol is used for the treatment of second-stage infection (involving the central nervous system). It is the only available therapy for second-stage Trypanosoma brucei rhodesiense (East African) infection. Melarsoprol is a prodrug, upon administration it is metabolized to the active form melarsen oxide, which acts by interacting with protein sulfhydryl groups and subsequently inactivating enzymes. A small but adequate amount of the drug penetrates the cerebrospinal fluid, where it is taken up and concentrated by trypanosomes. Due to the high toxicity of the drug, it is administered only in the most dangerous cases. Melarsoprol is not commercially available in the USA, but it is available as treatment IND from CDC.

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.

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