Fumagillin, an antimicrobial compound first isolated in 1949 from the fungus Aspergillus fumigatusa, naturally occurring water-insoluble antibacterial agent developed by sanofi-aventis, is approved in France for the treatment of microsporidiosis. Fumagillin (Flisint, Sanofi-Aventis, Paris, France) has been approved in France since 2002 for the treatment of intestinal microsporidiosis due to E. bieneusi in patients with AIDS, and is also available through an expanded access program for patients without AIDS. It has not been approved, however, by the US Food and Drug Administration. The discovery of fumagillin, a MetAP-2 inhibitor, with potent antiangiogenic and antiproliferative activities promoted the development of fumagillin analogues as a novel class of anticancer agents. It has been the subject of research in cancer treatments by employing its angiogenesis inhibitory properties.

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.

Amodiaquine is a medication used to treat malaria, including Plasmodium falciparum malaria when uncomplicated. The mechanism of plasmodicidal action of amodiaquine is not completely certain. Like other quinoline derivatives, it is thought to inhibit heme polymerase activity. This results in accumulation of free heme, which is toxic to the parasites. The drug binds the free heme preventing the parasite from converting it to a form less toxic. This drug-heme complex is toxic and disrupts membrane function. The side effects of amodiaquine are generally minor to moderate and are similar to those of chloroquine. Rarely liver problems or low blood cell levels may occur. When taken in excess headaches, trouble seeing, seizures, and cardiac arrest may occur. After oral administration amodiaquine hydrochloride is rapidly absorbed,and undergoes rapid and extensive metabolism to desethylamodiaquine which concentrates in red blood cells. It is likely that desethylamodiaquine, not amodiaquine, is responsible for most of the observed antimalarial activity, and that the toxic effects of amodiaquine after oral administration may in part be due to desethylamodiaquine.

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.

Nitrofurazone is used to treat burns that have become infected. It is also used to treat skin infections due to skin grafts. It works by killing bacteria or preventing their growth. The exact mechanism of action is unknown. Nitrofurazone inhibits several bacterial enzymes, especially those involved in the aerobic and anaerobic degradation of glucose and pyruvate. The severe or irreversible adverse effects of Nitrofurazone, which give rise to further complications include Peripheral neuropathy, Thromboembolic disorder.

Quinacrine was initially developed as an anti-malarial drug marketed under the name Atabrine. Also it was approved for the teratment of ascites, however it was wothdrawn for both indication in 1995 and 2003, respectively. The drug is also used for the treatment of giardiasis, lupus, rheumatoid arthritis, refractory pulmonary effusion and pneumothorax, induce female sterilization etc. Proposed mechanisms of action include DNA intercalation interference with RNA transcription and translation, inhibition of succinate oxidation interference with electron transport, inhibition of cholinesterase, and inhibitor of phospholipase.

Azanidazole (or Triclose), an antitrichomonal agent that is used to treat the vaginal trichomoniasis in Italy. This drug causes genotoxicity in liver and kidney that is not separated from its biological activity.

CHINIOFON, an iodoxyquinolin sulphonate derivative, is an antiprotozoal agent used in the treatment of amebiasis. It radiolabelled form can be used in radioisotope scanning.

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.

Diloxanide (used in the form of furoate) was developed for the treatment of intestinal amoebiasis. The effectiveness of the drug was proved in clinical trials, however, the mechanism of its action is unknown. The drug is not marketed in the United States, athough it is available in India.