[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Other antiprotozoals](https://durgical.com/en/pharmacology/classes/other-antiprotozoals/) › Nitazoxanide

# Nitazoxanide

## Other antiprotozoals?

Other antiprotozoals

Oral broad-spectrum antiparasitic for diarrhoea caused by Giardia and Cryptosporidium; well tolerated, it may tint the urine.

Updated Nov 1, 2026

## Quick facts

**Group**
[Other antiprotozoals](https://durgical.com/en/pharmacology/classes/other-antiprotozoals/)

**Target**
Pyruvate-ferredoxin oxidoreductase (PFOR) of anaerobic protozoa and bacteria

**Used for**
Diarrhoea caused by Giardia · Intestinal amoebiasis

**Key effects**
Abdominal pain · Headache · Nausea

**Monitor**
Number of stools and hydration

**ATC**
P01AX11

No doses: the clinician sets them by the current guideline.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

A nitrothiazolyl-salicylamide. In the gut it is quickly hydrolysed to tizoxanide, its active metabolite. Tizoxanide interferes with the electron-transfer reaction of pyruvate-ferredoxin oxidoreductase (PFOR), an enzyme that anaerobic protozoa such as Giardia and Cryptosporidium need to make energy from pyruvate; humans do not use this enzyme. It also acts on Entamoeba histolytica, some helminths and some anaerobic bacteria.

- Hydrolysed to active tizoxanide
- Blocks electron transfer by PFOR
- Anaerobic energy metabolism fails
- Giardia and Cryptosporidium die

## Indications

- Diarrhoea caused by Giardia in adults and children over one year [Giardiasis →](https://durgical.com/en/conditions/giardiasis/)
- Diarrhoea caused by Cryptosporidium in immunocompetent people (less effective in immunocompromised people) [Cryptosporidiosis and other intestinal coccidia (Cyclospora, Cystoisospora) →](https://durgical.com/en/conditions/cryptosporidiosis-and-other-intestinal-coccidia/)
- Intestinal amoebiasis and mixed intestinal parasitic infections (off-label use) [Intestinal amoebiasis (amoebic dysentery) →](https://durgical.com/en/conditions/intestinal-amoebiasis/)

## Adverse effects

### Common

- Abdominal pain
- Headache
- Nausea
- Discoloured (greenish-yellow) urine

### Serious (rare, important)

- Serious reactions are rare; allergic reactions are possible

## Contraindications

- Hypersensitivity to nitazoxanide
- Caution: liver or kidney disease

## Key interactions

**Other medicines and supplements**
No major interactions are named in patient information; all medicines are still reviewed before starting

## What is monitored

- Number of stools and hydration
- Clinical response after the short course; in immunocompromised people, response is often incomplete
- Stool tests when diarrhoea persists

## Administration and safety

- Oral tablets or suspension, with food, as a short course.
- The suspension is shaken well; unused suspension is discarded after a set number of days.
- Fluids are given to prevent dehydration.

## Pregnancy and breastfeeding

Generally considered low risk in pregnancy, but human data are limited and the prescriber weighs the need.

## Nursing care

- Assess hydration (weight, urine output, mucous membranes) in children with diarrhoea.
- Explain that the urine may change colour and that this is harmless.
- Teaching: drink plenty of fluids, finish the course and wash hands well to avoid spreading the parasite.
- Report persistent diarrhoea, especially in people with HIV or other immune problems.

## Pharmacokinetics

**Absorption**
Oral; rapidly converted to tizoxanide; taken with food

**Distribution**
Tizoxanide is more than 99.9 % bound to plasma proteins

**Metabolism**
Hydrolysis to tizoxanide, then glucuronide conjugation

**Elimination**
Urine, bile and faeces

## Memory aid

«NITA's GC tour»: NITAzoxanide clears Giardia and Cryptosporidium, and leaves a Coloured urine souvenir.

## Test yourself

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

## Which two protozoa are nitazoxanide's main targets?

Giardia (giardiasis) and Cryptosporidium (cryptosporidiosis).

## Which enzyme does its active metabolite inhibit?

Pyruvate-ferredoxin oxidoreductase (PFOR), needed for the energy metabolism of anaerobic protozoa.

## In which patients is it less effective against Cryptosporidium?

In immunocompromised people, such as those with advanced HIV; restoring immune function is the key measure.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/nitazoxanide/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 2

- [Metronidazole](https://durgical.com/en/pharmacology/metronidazole/)
- [Tinidazole](https://durgical.com/en/pharmacology/tinidazole/)

## Related conditions 3

- [Giardiasis](https://durgical.com/en/conditions/giardiasis/)
- [Cryptosporidiosis and other intestinal coccidia (Cyclospora, Cystoisospora)](https://durgical.com/en/conditions/cryptosporidiosis-and-other-intestinal-coccidia/)
- [Intestinal amoebiasis (amoebic dysentery)](https://durgical.com/en/conditions/intestinal-amoebiasis/)

[← Back to the class: Other antiprotozoals](https://durgical.com/en/pharmacology/classes/other-antiprotozoals/)

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

Sources: [Nitazoxanide: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a603017.html) (MedlinePlus (U.S. National Library of Medicine), 2025); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=P01AX) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/nitazoxanide/