niridazole

Description

Niridazole is a yellow, crystalline solid. It is almost insoluble in water and most organic solvents, but it is soluble in dimethylformamide.

The Uses of niridazole

Antischistosomal.

Definition

ChEBI: Niridazole is a C-nitro compound and a member of 1,3-thiazoles.

Indications

Niridazole can be used against blood flukes, especially Schistosoma haematobium. Tolerance and efficacy are reduced in S. mansoni and especially in S. japonicum infections. It is also used in Dracunculus infections. Immunosuppression, vomiting, cramps, dizziness, and headache are among the frequent adverse reactions.

Mechanism of action

Niridazole causes a depletion of glycogen in schistosomes by inducing a reduced rate of conversion of active glycogen phosphorylase to its inactive form. This is achieved through inhibition of the enzyme phosphorylase phosphatase, which normally inactivates glycogen phosphorylase. It is possible that the active moiety is not niridazole, but its 5-imino analog, which can be formed by schistosomes in vitro under anaerobic conditions .

Pharmacology

Niridazole exhibits schistosomicide and amebicidal action. The mechanism of action is not known. It seems likely that it is concentrated in the parasite organism, which causes inhibition of phosphorylase activation, which is expressed in the depletion of glycogen reserves.
It also may inhibit spermatogenesis of parasites by affecting the production of eggs. It is used for diseases caused by Dracunculus meddinesis, as well as Shistosoma haematobium and Shistosoma mansoni. It belongs to a group of tertiary drugs and is used only in the absence of the drug of choice. Synonyms of this drug are ambilhar and others.

Side Effects

Occasional adverse reactions are diarrhea, electrocardiographic changes, rash, insomnia, and paresthesia. Psychosis, hemolytic anemia, and convulsions are rare. Contraindications are impaired liver function, glucose-6- phosphatedehydrogenase deficiency, epilepsy, and severe heart diseases.

Safety Profile

Confirmed carcinogen with experimental carcinogenic and neoplastigenic data. Poison by intraperitoneal route. Moderately toxic by ingestion. Experimental reproductive effects. Human mutation data reported. Used as an amoebicide and schistosomicidal agent.

Synthesis

Niridazole, 1-(5-nitro-2-thiazolyl)-2-imidazolidinone (38.1.11), is made by reacting 2-amino-5-nitrothiazol with 2-chloroethylisocyanate to make the disubstituted urea (38.1.10). Heating this compound results in an intramolecular N-alkylation reaction to form the desired imidazolidine derivative, niridazole.