benznidazole

Action and Spectrum

Actions and Spectrum 

The nitroimidazole class includes benznidazole, which works by interfering with the parasite’s ability to metabolise energy. Being a prodrug, its effectiveness depends on the parasite’s metabolic activity. In the end, this kills the parasite or prevents its growth. 

The main indication for benznidazole is the treatment of Chagas disease, which is brought on by the protozoan parasite Trypanosoma cruzi. 

Drug Interaction

Adverse Reaction

Frequency defined  

1-10% 

Diarrhea (4%) 

Peripheral neuropathy (2%) 

Tremor (2%) 

Dizziness (4%) 

Vomiting (5%) 

Increased ALT/AST (5%) 

Nausea (5%) 

>10% 

Rash or skin lesions (11-16%) 

Weight decreased (13%) 

Abdominal pain (25%) 

Post marketing reports 

Severe irreversible acute liver failure or hepatotoxicity 

Black Box Warning

Black Box Warning 

benznidazole drug does not have any black box warning. 

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

• People with known hypersensitivity or allergy to benznidazole or any of its ingredients should not use it. 

Caution: 

• It is necessary to carefully consider whether using benznidazole during pregnancy or breast-feeding.  
• care should be used while giving the medication to people whose liver function is compromised.  
• benznidazole is not predominantly excreted through the kidneys, people with compromised renal function should nevertheless use the medication with caution. 

Pregnancy / Lactation

Pregnancy warnings:     

Pregnancy category: N/A 

Lactation: Excretion into human milk is known  

Pregnancy Categories:         

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women.    

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women. 

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits. 

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.  

Category N: There is no data available for the drug under this category. 

Pharmacology

Pharmacology  

As it is a prodrug, its pharmacological effects depend on metabolic activation. The nitro reductase enzyme system reduces benznidazole inside the parasite, resulting in the generation of reactive metabolites.  

These metabolites harm the parasite’s DNA and other cellular components, ultimately causing death or preventing further growth. 

Pharmacodynamics 

The nitro reductase enzyme system found in Trypanosoma cruzi helps in the activation of benznidazole within the parasite. By reducing the nitro group in benznidazole, this mechanism creates toxic metabolites that give the drug its antiparasitic properties. 

benznidazole exhibits a stronger affinity for the parasite Trypanosoma cruzi. This targeted activity aids in eliminating the parasite while minimizing damage to the host cells. 

Pharmacokinetics 

Absorption   

benznidazole is effectively absorbed after being administered orally. It absorbs quickly and thoroughly from the gastrointestinal system, reaching peak plasma concentrations in one to three hours.  

Distribution 

The moderate volume of distribution of benznidazole suggests that it disperses quite widely throughout the body. It has been discovered in CSF fluid and it is able to cross the blood-brain barrier.  

Metabolism 

In the liver, benznidazole is extensively metabolized. It mostly undergoes reduction, hydroxylation, and conjugation events during metabolism. Hepatic enzymes, such as cytochrome P450 enzymes, are involved in the metabolism of benznidazole. 

Elimination and excretion 

The kidneys are the main organs via which benznidazole, and its metabolites are excreted. The medication and its metabolites are primarily eliminated in the urine. A smaller portion is eliminated by feces. benznidazole has an elimination half-life of 12 to 24 hours. 

Adminstartion

Administration 

For oral use, benznidazole is available in tablet form.  

To optimise absorption and decrease gastrointestinal adverse effects, the tablet should be taken whole, with water, and with meals. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: benznidazole 

Why do we use benznidazole? 

Chagas disease, a protozoan parasite infection caused by Trypanosoma cruzi, is treated with benznidazole.