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[Pharmacology](https://durgical.com/en/pharmacology/) · Class

# Antitrypanosomals

Drugs against trypanosomes: benznidazole and nifurtimox cure Chagas disease when given early; others treat African sleeping sickness.

Updated 2026-11-01

## What they are

Antiprotozoal drugs against Trypanosoma cruzi (Chagas disease, endemic in Colombia and Latin America) and T. brucei (African sleeping sickness). Chagas disease has only two: benznidazole and nifurtimox.

## Mechanism of action

Benznidazole (a nitroimidazole) and nifurtimox (a nitrofuran) are prodrugs: a parasite mitochondrial nitroreductase reduces them to radicals and reactive metabolites that damage the parasite's DNA, lipids and proteins. They act on blood trypomastigotes and tissue amastigotes.

Target: Parasite nitroreductase (activates the nitro drugs)

## Key points

- Chagas: benznidazole (preferred) or nifurtimox; they cure most acute and congenital infections.
- In the chronic phase efficacy falls, but treatment can slow progression; it does not reverse established cardiomyopathy or megaoesophagus.
- Treating girls and women of childbearing age before pregnancy prevents congenital transmission, now the main route worldwide.
- Adverse effects are common and worse with age: dermatitis (benznidazole), anorexia and weight loss (nifurtimox), peripheral neuropathy (both).
- Not given in pregnancy or in severe kidney or liver failure.

## Drugs in this class

- [**Benznidazole** The preferred drug for Chagas disease: it cures acute and congenital infection; its most typical adverse effect is… Trypanosoma cruzi type I nitroreductase (activates the prodrug)](https://durgical.com/en/pharmacology/benznidazole/)
- [**Nifurtimox** Oral nitrofuran for Chagas disease, the alternative to benznidazole; it often causes loss of appetite, weight loss and… Trypanosoma cruzi nitroreductase (activates the prodrug)](https://durgical.com/en/pharmacology/nifurtimox/)
- [**Pentamidine** Parenteral diamidine for Pneumocystis pneumonia, leishmaniasis and early sleeping sickness; it can cause severe… Several parasite targets (DNA, RNA, phospholipid and protein synthesis)](https://durgical.com/en/pharmacology/pentamidine/)

## Others in the class

- Suramin sodium
- Melarsoprol
- Eflornithine
- Fexinidazole

## Test yourself

Think of the answer, then tap the question to see it.

## Which two drugs cure Chagas disease?

Benznidazole and nifurtimox, both nitro prodrugs activated by the parasite itself.

## In which phase of Chagas disease do they work best?

In the acute phase, including congenital infection; in the chronic phase efficacy falls with years of infection.

## Why are women of childbearing age with chronic Chagas disease treated?

To prevent them passing the parasite to their babies in a future pregnancy (congenital transmission).

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Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Chagas disease (also known as American trypanosomiasis)](https://www.who.int/news-room/fact-sheets/detail/chagas-disease-(american-trypanosomiasis)) (World Health Organization, 2025); [Clinical Care of Chagas Disease](https://www.cdc.gov/chagas/hcp/clinical-care/index.html) (Centers for Disease Control and Prevention (CDC), 2024); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=P01C) (WHO Collaborating Centre for Drug Statistics Methodology, 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 67 (McGraw Hill, 2023).

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Representative model, for educational purposes only.

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