nifurtimox

Absorption

The average AUC of nifurtimox is estimated between 1676-2670 μg?h/L. One pharmacokinetic study of healthy volunteers revealed an AUC of 5430 ng?ml-1?h. Cmax ranges between 425-568 μg/L (26–50%) after a single dose of 20 mg with food in adults. Tmax is 4 hours, ranging from 2 to 8 hours post-dose in the fed state. In a pharmacokinetic study of healthy volunteers, serum concentration was low, likely due to the first-pass effect.

Toxicity

There is limited information in the literature regarding overdose with nifurtimox. Some symptoms of nifurtimox toxicity may include weight loss, anorexia, nausea, vomiting, vertigo, headache, nervous excitation, insomnia, convulsions, drowsiness, arthralgias, myalgias, disorientation, abdominal pain, mucosal edema, and skin manifestations. These symptoms are adverse effects of nifurtimox and are likely to be exaggerated with increased exposure.

Description

Nifurtimox is manufactured by Bayer and marketed under the trade name Lampits.It is a nitrofuran derivative that was developed specifically for the treatment of American trypanosomiasis (Chagas'disease) (Packachanian, 1957). Nifurtimox is one of two drugs approved for use in treatment of Chagasdisease. It was shown to be the most active and least toxic of this group of agents in preclinical studies and was evaluated in clinical trials in the 1960s and subsequently marketed for use in Chagas’ disease in Latin America in the late 1960s and early 1970s. Although the use of nifurtimox for Chagas’ disease has decreased with the availability of benznidazole, a potentially more active and less toxic agent, there has been a resurgence of interest in and use of nifurtimox for the treatment of second-stage human African trypanosomiasis (HAT)caused by Trypanosoma brucei gambiense.

Chemical properties

Orange Solid

The Uses of nifurtimox

The nitrofuran nifurtimoxis the most effective drug against T. cruzi, being cidal against the trypomastigote and amastigote forms. It is active against both the extra- and intracellular form of the parasite. In combination with corticosteroids it has prevented myocardial inflammation and destroyed the parasites within the heart. Side effects of the drug tend to be mild and include nausea, vomiting, insomnia, nervous excitation, vertigo, and skin rashes. Cardiac symptoms are treated symptomatically. Benznidazole (2, C12H12N4O3, N-benzyl-2-nitro-1 imidazoleacetamide, RO 7-1051), an alternative drug, can prevent the spread of the parasites from one tissue to another although relapses are common. Primaquine can destroy the extracellular trypanosomes in the blood, but is not effective against the intracellular forms of the parasite.

The Uses of nifurtimox

Antiprotozoal (Trypanosoma). Showing anti-Trypanosoma cruzi activity.

Background

Chagas disease, caused by a parasite known as Trypanosoma cruzi (T.cruzi), is a vector-transmitted disease affecting animals and humans in the Americas. It is commonly known as American Trypanosomiasis.
The CDC estimates that approximately 8 million people in Central America, South America, and Mexico are infected with T. cruzi, without symptoms. If Chagas disease is left untreated, life-threatening sequelae may result.
Nifurtimox, developed by Bayer, is a nitrofuran antiprotozoal drug used in the treatment of Chagas disease. On August 6 2020, accelerated FDA approval was granted for its use in pediatric patients in response to promising results from phase III clinical trials. Continued approval will be contingent upon confirmatory data. A convenient feature of Bayer's formulation is the ability to divide the scored tablets manually without the need for pill-cutting devices.

Indications

Nifurtimox is indicated in pediatric patients under 18 weighing at least 2.5 kg. Continued approval of this drug for this indication is dependent upon confirmatory clinical trial results.

What are the applications of Application

Nifurtimox is a nitrofuran antiprotazoal

Indications

Nifurtimox (Lampit) is a nitrofuran derivative whose likely mechanism of action for killing of trypanosomes is through the production of activated forms of oxygen. Nifurtimox is reduced to the nitro anion radical, which reacts with oxygen to produce superoxide and hydrogen peroxide. The free radical metabolites, an absence of parasite catalase, and a peroxide deficiency lead to lipid peroxidation and cell damage. This production of activated oxygen results in toxicity to the protozoal cells.

Definition

ChEBI: Nifurtimox is a nitrofuran antibiotic.

General Description

Nifurtimox acts as a hypoxia-activated cytotoxin, which specifically kills clonogenic tumor cells under hypoxic conditions. It is used to treat Chagas disease and African trypanosomiasis. Nifurtimox inhibits neuroblastoma and medulloblastoma cell growth.

Pharmaceutical Applications

A water-soluble synthetic compound available for oral use. It exhibits antibacterial activity typical of the group, but its most notable property is its activity against trypanosomes, especially Trypanosoma cruzi.
A plasma concentration of 0.5–1 mg/L is achieved c. 2 h after an oral dose of 15 mg/kg. The plasma half-life is 2–4 h. In common with other nitrofurans, it is rapidly and extensively metabolized, so that less than 1% of a dose is excreted intact in the urine. In renal failure, clearance is somewhat reduced but the half-life is unchanged.
Adverse events are common. Many patients experience anorexia, which may be combined with vomiting and abdominal pain. There may also be neurological reactions such as restlessness, insomnia, headache and disorientation.
It is used in the treatment of Chagas disease (South American trypanosomiasis). It has also found some use in the treatment of African sleeping sickness in combination with eflornithine.

Biochem/physiol Actions

Nifurtimox is a nitrofurane derivative used to treat diseases caused by trypanosomes. Nifurtimox was discovered empirically and its mechanism of action is unclear. It is believed that nifurtimox exerts its biological activity through the bioreduction of the nitro-group to a nitro-anion radical which undergoes redox-cycling with molecular oxygen.

Mechanism of action

The drug is given orally and is well absorbed from the gastrointestinal tract. It is rapidly metabolized, and only low levels are found in blood and tissues.The drug is excreted in the urine, primarily in the form of metabolites.

Pharmacokinetics

Nifurtimox exerts trypanosomal activity against Trypanosoma cruzi, treating Chagas disease. One study reports that nifurtimox and other benzofuran derivatives reduce parasite dehydrogenase activity. Results of a recent phase III clinical trial have shown that a significant number of pediatric patients with acute or chronic Chagas disease treated with nifurtimox were immunoglobulin G (IgG) antibody negative and demonstrated at least a 20% decrease in optical density on two IgG antibody tests for T. cruzi antigens.

Clinical Use

Nifurtimox is trypanocidal and exerts an effect on the trypomastigote and amastigote forms of T. cruzi. It is effective in the treatment of the acute form of Chagas’ disease but is less effective once the disease becomes chronic. The drug is moderately well tolerated, and treatment generally lasts 3 to 4 months. Cure rates of 80 to 90% have been reported. Since much of the tissue damage caused by the disease is irreversible, early diagnosis and treatment are important. Nifurtimox has also been used in T. gambiense infection with meningoencephalopathic involvement.

Side Effects

Although side effects occur in approximately half the patients treated with nifurtimox, it is necessary to discontinue treatment in only a minority. Nausea, vomiting, abdominal pain, skin rashes, headache, insomnia, convulsions, and myalgia all have been reported.

Synthesis

Nifurtimox, 1,1-dioxide 4-[(5-nitrofuryliden)amino]-3-methylthiomorpholine (37.4.7), is made by the following scheme. Interaction of 2-mercaptoethanol with propylene oxide in the presence of potassium hydroxide gives (2-hydroxyethyl)-(2-hydroxypropylsulfide) (37.4.3), which undergoes intramolecular dehydration using potassium bisulfate to make 2-methyl-1,4-oxithiane (37.4.4). Oxidation of this using hydrogen peroxide gives 2-methyl-1,4-oxithian-4,4-dioxide (37.4.5), which when reacted with hydrazine transforms to 4-amino-3-methyltetrahydro-1,4-thiazin-1,1-dioxide (37.4.6). Reacting this with 5-nitrofurfurol gives the corresponding hydrazone?athe desired nifurtimox.

Metabolism

Nifurtimox is largely metabolized via nitroreductase enzymes. Two major inactive metabolites have been identified: M-4 and M-6. The M-4 metabolite is a cysteine conjugate of nifurtimox, while M-6 is likely formed by hydrolytic cleavage of the hydrazone moiety of nifurtimox. Other minor metabolites have also been identified in human plasma.