Organoarsenic dithiolates

Melarsoprol is an arsenic-containing medication used for the treatment of sleeping sickness (African trypanosomiasis). It is specifically used for second-stage disease caused by Trypanosoma brucei rhodesiense when the central nervous system is involved. For Trypanosoma brucei gambiense, eflornithine or fexinidazole is usually preferred. It is effective in about 95% of people. It is given by injection and is known by patients as "fire in the veins".

Arsthinol (INN) is an organoarsenic compound with the formula . A antiprotozoal agent, it was first reported in 1949. It arises by the reaction of acetarsol with 2,3-dimercaptopropanol (British anti-Lewisite) and has been demonstrated to be effective against amoebiasis and yaws. It was marketed a few years later by Endo Products (Balarsen, Tablets, 0.1 g).

Arsenamide or thiacetarsamide (trade name Caparsolate) is an arsenical. It is a proposed chemotherapeutic agent against canine filaria and trichomonas.

Melarsomine (melaminylthioarsenate) is an arsenic-based anthelmintic. In the U.S., it is marketed under the trade names Immiticide (Merial) and Diroban (Zoetis), and is approved by the FDA's Center for Veterinary Medicine for the treatment of adult heartworm (Dirofilaria immitis) infection in dogs. It is not approved for treatment in cats, or dogs in late-stage infection.