Nanazoxid® 500 mg Film-Coated Tablets — Nitazoxanide — Antiprotozoal
1- Disclaimer
This information is intended for educational and general drug-information purposes and does not replace the advice, diagnosis, prescription, or follow-up of a qualified physician or pharmacist. Treatment decisions should be individualized according to the patient's diagnosis, age, medical history, immune status, concomitant medicines, and the official locally approved product information.
We do not guarantee the accuracy, currency or completeness of information regarding medications or medical products, and official sources should be verified before making any decisions. Readers are responsible for independently verifying the information before relying on it.
2- Summary
Nanazoxid is an oral antiparasitic medicine containing nitazoxanide. The 500 mg film-coated tablet is used primarily for the treatment of diarrhea caused by Giardia lamblia (also known as Giardia duodenalis) or Cryptosporidium parvum.
The current Utopia Pharmaceutical product page lists Nanazoxid Tablets 500 mg and Nanazoxid Oral Suspension 100 mg/5 mL. The tablet formulation is intended for patients 12 years of age and older for its labeled protozoal indications.
3- Brand Name
Nanazoxid®
4- Category
Antiprotozoal / antiparasitic agent.
For the approved/labeled gastrointestinal uses of nitazoxanide, “antiprotozoal” is more precise than describing the product solely as an antihelminthic. Nitazoxanide has been studied against other organisms, but such activity should not be interpreted as an approved indication for Nanazoxid.
5- Active Ingredient
Each film-coated tablet contains:
Nitazoxanide 500 mg
Chemical name: 2-acetyloxy-N-(5-nitro-2-thiazolyl)benzamide
Molecular formula: C₁₂H₉N₃O₅S
Molecular weight: approximately 307.3 g/mol.
6- Pharmaceutical Form & Strength
Film-coated tablet: Nitazoxanide 500 mg.
A separate Nanazoxid formulation is currently listed as powder/oral suspension 100 mg/5 mL after reconstitution.
Current Egyptian pharmacy listings show the 500 mg presentation in packs of 18 film-coated tablets.
7- Manufacturer & Marketing Authorization Holder
Current Egyptian retail and drug-database listings identify:
Manufacturer: Medizen Pharmaceutical Industries.
Brand/company: Utopia Pharmaceuticals.
Current Egyptian listings and published Egyptian sources have identified Nanazoxid as manufactured by Medizen Pharmaceutical Industries for Utopia Pharmaceuticals. Utopia Pharmaceutical Industries currently lists Nanazoxid among its pharmaceutical products. Manufacturer and marketing-authorization details may depend on the currently marketed product and registration status; therefore, the legally controlling information is that printed on the current Egyptian carton and approved package leaflet or recorded by the relevant Egyptian regulatory authority.
8- Mechanism of Action
Nitazoxanide is rapidly converted after oral administration to its active metabolite tizoxanide.
Its antiprotozoal effect is believed to result mainly from interference with the pyruvate:ferredoxin oxidoreductase (PFOR)-dependent electron-transfer reaction, which is essential for anaerobic energy metabolism in susceptible organisms.
PFOR inhibition may not be the only mechanism responsible for its antiprotozoal activity.
9- Spectrum of Activity
Nitazoxanide and tizoxanide demonstrate activity against:
- Giardia lamblia: particularly trophozoites.
- Cryptosporidium parvum: including inhibition of sporozoites and oocysts in vitro.
Standardized clinical-microbiology susceptibility testing methods for these protozoa are not routinely available, and the potential for development of resistance by G. lamblia or C. parvum has not been adequately characterized.
The presence of experimental activity against other parasites, bacteria, or viruses does not establish routine clinical efficacy or an approved indication for those infections.
10- Pharmacokinetics
Absorption: After oral administration, unchanged nitazoxanide is generally not detectable in plasma because it is rapidly converted to tizoxanide. Following a 500 mg tablet taken with food, peak plasma concentrations of tizoxanide are generally reached within a few hours.
Effect of food: Food substantially increases systemic exposure. With tablets, the AUC of tizoxanide and tizoxanide glucuronide increases to almost twice the fasting exposure and Cmax increases by approximately 50%. Therefore, tablets should be taken with food.
Distribution: Tizoxanide is very highly bound to plasma proteins (>99%); the drug-interaction section of current U.S. prescribing information reports protein binding of >99.9%.
Metabolism: Nitazoxanide is rapidly hydrolyzed to tizoxanide, which subsequently undergoes conjugation, mainly glucuronidation.
Excretion: Tizoxanide is eliminated in urine, bile, and feces; tizoxanide glucuronide is eliminated in urine and bile. Approximately two-thirds of an oral dose is recovered in feces and about one-third in urine.
There is no significant accumulation of tizoxanide or tizoxanide glucuronide during repeated administration every 12 hours in available pharmacokinetic studies.
In-vitro studies indicate that tizoxanide does not significantly inhibit cytochrome P450 enzymes.
11- Indications
Nanazoxid 500 mg tablets are indicated for the treatment of diarrhea caused by:
Giardia lamblia
Cryptosporidium parvum
The current Utopia product information specifies the tablet formulation for patients 12 years of age and older.
For C. parvum, nitazoxanide has not been shown to be effective in HIV-infected or other immunodeficient patients. CDC information similarly notes that effectiveness in people with weakened immune systems remains unclear.
Nitazoxanide should not be regarded as a nonspecific treatment for diarrhea of any cause.
12- Administration
For adults and adolescents 12 years of age and older with diarrhea caused by G. lamblia or C. parvum:
500 mg orally every 12 hours with food for 3 days.
Food is important because it substantially increases exposure to the active metabolites.
The 500 mg tablet should not be used to provide pediatric doses in children 11 years of age or younger, because one tablet contains more nitazoxanide than the recommended pediatric dose. Appropriate oral-suspension dosing should be used when clinically indicated.
13- Method of Preparation
No preparation or reconstitution is required for the 500 mg film-coated tablet.
The tablet is administered orally with food.
Nanazoxid 100 mg/5 mL oral suspension is a separate pharmaceutical formulation that requires preparation/reconstitution according to the instructions supplied with that product.
14- Contraindications
Nanazoxid is contraindicated in patients with:
Known hypersensitivity to nitazoxanide or to any component of the formulation.
15- Warnings & Precautions
Renal or hepatic impairment: The pharmacokinetics of nitazoxanide in patients with compromised renal or hepatic function have not been studied. No specific evidence-based dose adjustment has therefore been established for these populations. Treatment should be individualized using appropriate clinical judgment.
Immunodeficiency: For diarrhea caused by G. lamblia, nitazoxanide has not been studied in HIV-infected or other immunodeficient patients. For diarrhea caused by C. parvum, nitazoxanide has not been shown to be superior to placebo in HIV-infected or other immunodeficient patients.
Persistent diarrhea: Persistent or worsening diarrhea may require reassessment for dehydration, reinfection, another pathogen, or an alternative diagnosis rather than simply extending therapy without medical evaluation.
Adequate fluid replacement is particularly important in patients with significant diarrhea.
Seek prompt medical attention for severe dehydration, persistent vomiting, blood in stool, severe abdominal symptoms, or signs of a serious allergic reaction.
16- Drug Interactions
The active metabolite tizoxanide is very highly plasma-protein bound (>99.9%). Competition for protein-binding sites may therefore occur when nitazoxanide is administered together with other highly protein-bound drugs that have a narrow therapeutic index.
Particular attention is warranted with warfarin. Current U.S. prescribing information recommends monitoring for adverse reactions when nitazoxanide is administered concurrently with highly protein-bound, narrow-therapeutic-index drugs such as warfarin, while its patient-counseling information specifically advises avoiding concurrent warfarin use. If concomitant treatment is considered clinically necessary, appropriate medical supervision and monitoring of anticoagulation and adverse effects are warranted.
In-vitro data indicate that tizoxanide does not significantly inhibit cytochrome P450 enzymes.
17- Side Effects
The most commonly reported adverse reactions in controlled clinical trials, occurring in at least approximately 2% of patients, include:
Abdominal pain, headache, chromaturia (urine discoloration), and nausea.
Post-marketing adverse reactions have included:
Gastrointestinal: diarrhea and gastroesophageal reflux.
Nervous system: dizziness.
Respiratory: dyspnea.
Skin/hypersensitivity: rash and urticaria.
Patients who develop symptoms suggesting significant hypersensitivity, particularly urticaria associated with breathing difficulty or facial/throat swelling, should seek urgent medical care.
18- Use in Special Populations
Pregnancy: Adequate human pregnancy data are not available to define a drug-associated risk. Animal reproductive studies have not demonstrated teratogenicity or fetotoxicity at the exposures evaluated. Nitazoxanide during pregnancy should therefore be used after appropriate assessment of clinical need and potential benefit versus uncertainty.
Breastfeeding: Current U.S. prescribing information states that adequate information is not available regarding the presence of nitazoxanide in human milk, its effects on the breastfed infant, or its effects on milk production. Separately, LactMed reports limited human data showing that a single maternal 500 mg dose resulted in a relatively low concentration of the active metabolite tizoxanide in breast milk and would not be expected to cause adverse effects in breastfed infants, particularly those older than two months. However, the evidence remains limited, and LactMed notes that an alternative drug may be preferred when nursing a newborn or premature infant. The developmental and health benefits of breastfeeding should be considered together with the mother's clinical need for treatment and any potential risk to the infant.
Pediatric patients: The 500 mg tablet is intended for patients 12 years and older. For ages 1–3 years, the established nitazoxanide suspension dose is 100 mg every 12 hours with food for 3 days; for ages 4–11 years, 200 mg every 12 hours with food for 3 days. Safety and efficacy in infants younger than one year have not been established.
Older adults: Clinical studies included insufficient numbers of patients aged 65 years or older to determine whether their response differs from younger adults. Reduced renal, hepatic, or cardiac function and concomitant medications should be considered.
Renal/hepatic impairment: Specific pharmacokinetic studies in patients with compromised renal or hepatic function are lacking. Consequently, no specific evidence-based dosage adjustment has been established for these populations.
19- Storage Conditions
Store Nanazoxid according to the instructions on the current package.
For the Egyptian tablet formulation, storage instructions specify:
Keep at a temperature not exceeding 30°C, in a dry place.
Keep the medicine in its original packaging and out of the reach of children.
20- Additional Sections
Overdosage: Information on nitazoxanide overdose is limited. There is no specific antidote. Patients should be observed and treated with appropriate symptomatic and supportive care. Gastric lavage may be considered by medical professionals when clinically appropriate soon after a significant ingestion. Because tizoxanide is extremely highly protein-bound, dialysis is unlikely to substantially reduce circulating concentrations.
Current Egyptian presentation: Current Egyptian pharmacy listings show Nanazoxid 500 mg as a pack containing 18 film-coated tablets. Pack sizes can change, so the current marketed carton should be regarded as authoritative.
Treatment response: In clinical trials of giardiasis and cryptosporidiosis, symptomatic improvement does not necessarily mean that every follow-up stool specimen will immediately be parasite-negative. Clinical reassessment is appropriate when symptoms persist.
Cryptosporidiosis and transmission: Because Cryptosporidium can continue to be shed after symptoms resolve and is highly resistant to routine pool chlorination, CDC recommends avoiding swimming for 2 weeks after diarrhea has completely resolved.
21- Frequently Asked Questions (FAQ)
Q: What is Nanazoxid 500 mg mainly used for?
A: It is used for diarrhea caused by Giardia lamblia or Cryptosporidium parvum in patients 12 years of age and older.
Q: Should Nanazoxid be taken before or after food?
A: It should be taken with food, because food significantly increases absorption/exposure to its active metabolites.
Q: What is the usual dose of Nanazoxid 500 mg?
A: For its labeled protozoal indications in patients aged 12 years and older, the usual regimen is one 500 mg tablet every 12 hours with food for 3 days.
Q: Can a 500 mg tablet be given to a young child?
A: The 500 mg tablet should not be used in children 11 years of age or younger. The 100 mg/5 mL oral suspension permits age-appropriate pediatric dosing.
Q: Does Nanazoxid treat every type of diarrhea?
A: No. Diarrhea can have many infectious and noninfectious causes. The established labeled indications are diarrhea caused by G. lamblia and C. parvum.
Q: Is it effective for Cryptosporidium in immunocompromised patients?
A: It has not been shown to be superior to placebo for C. parvum-associated diarrhea in HIV-infected or other immunodeficient patients. For G. lamblia-associated diarrhea, use in HIV-infected or other immunodeficient patients has not been studied.
Q: Can Nanazoxid interact with warfarin?
A: Yes. Tizoxanide is extremely highly protein-bound, creating a potential for competition with warfarin for protein-binding sites. Current U.S. patient-counseling information advises avoiding concurrent warfarin use. If concomitant treatment is considered necessary by a clinician, appropriate monitoring of anticoagulation and adverse effects is warranted.
Q: Can it be used during pregnancy or breastfeeding?
A: Human pregnancy data remain limited. For breastfeeding, current U.S. prescribing information states that adequate information on nitazoxanide in human milk and its effects on the infant or milk production is unavailable. LactMed separately reports limited single-dose human data suggesting low tizoxanide exposure through breast milk, but the evidence remains limited. Individual medical assessment is recommended.
22- References
- Utopia Pharmaceutical Industries — Nanazoxid product information, current product page dated September 8, 2026: Nanazoxid tablets 500 mg and oral suspension 100 mg/5 mL; labeled therapeutic indications.
- U.S. National Library of Medicine, DailyMed — Nitazoxanide Tablets prescribing information, DailyMed page updated June 18, 2026; prescribing information revised September 2025. Includes indications, dosing, contraindications, adverse reactions, drug interactions, special populations, pharmacokinetics, microbiology, and overdose information.
- Centers for Disease Control and Prevention (CDC) — Clinical Care of Cryptosporidiosis, June 25, 2025. Includes nitazoxanide use in immunocompetent patients and limitations in immunocompromised patients.
- Drugs and Lactation Database (LactMed), U.S. National Library of Medicine — Nitazoxanide, revision September 15, 2023. Includes the limited available human breast-milk data for tizoxanide after maternal nitazoxanide administration.
- Current Egyptian pharmacy and drug-database listings — Nanazoxid 500 mg, supporting the currently listed 18-tablet presentation and identification of Medizen Pharmaceutical Industries as manufacturer for Utopia Pharmaceuticals; the current marketed carton and approved Egyptian product information remain authoritative for regulatory manufacturer/MAH details.