Nitazoxanide

Uses

Nitazoxanide is used for diarrhoea caused by Cryptosporidium parvum and Giardia lamblia, Amebiasis and helminth infections.

Nitazoxanide is also used to associated treatment for these conditions: Ascariasis, Cestode infections, Clostridium difficile infection recurrence, Cryptosporidiosis infection, Diarrhea caused by Cryptosporidium parvum, Diarrhea caused by Giardia lamblia, Giardiasis, Trichuriasis

How Nitazoxanide works

The most widely accepted mechanism of NTZ is believed to be the disruption of the energy metabolism in anaerobic microbes by inhibition of the pyruvate: ferredoxin/flavodoxin oxidoreductase (PFOR) cycle . In parasitic-protozoa, Nitazoxanide also induces lesions in the cell membranes and depolarizes the mitochondrial membrane while inhibiting quinone oxidoreductase NQO1, nitroreductase-1 and protein disulphide isomerase enzymes. In addition, this drug also inhibits the glutathione-S-transferase (a major detoxifying enzyme) and modulates the Avr-14 gene, encoding for the alpha-type subunit of glutamate-gated chloride ion channel present in nematodes. Aside from its well understood non-competitive inhibition of the PFOR in anaerobic bacteria, NTZ also demonstrates various other antibacterial mechanisms. It inhibits pyruvate dehydrogenase in E Coli, disrupts the membrane potential and pH homeostasis in the Mycobacterium tuberculosis, suppresses the chaperone/usher (CU) pathway of the gram-negative bacteria, and stimulates host macrophage autophagy in tuberculosis patients . NTZ also suppresses viral replication by inhibiting the maturation of the viral hemagglutinin and the viral transcription factor immediate early 2 (IE2) as well as by activating the eukaryotic translation initiation factor 2α (an antiviral intracellular protein). Lastly, NTZ exhibits an inhibitory effect on tumor cell progression by altering drug detoxification (glutathione-S-transferase P1), unfolded protein response, autophagy, anti-cytokines activity, and c-Myc inhibition .

Dosage

Nitazoxanide dosage

Age 1-3 years: 5 ml (100 mg) twice daily for 3 days

Age 4-11 years: 10 ml (200 mg) twice daily for 3 days

Age >12 years: 25 ml or 1 tablet (500 mg) twice daily for 3 days

The suspension or tablet should be taken with food.

30 ml suspension: Shake the bottle well before adding water. Then add 20 ml of boiled and cooled water (with the help of provided cup) into the bottle and shake well to make 30 ml suspension.

60 ml suspension: Shake the bottle well before adding water. Then add 40 ml of boiled and cooled water (with the help of provided cup) into the bottle and shake well to make 60 ml suspension.

Side Effects

Nitazoxanide is generally well tolerated. However abdominal pain, diarrhoea vomiting and headache have been reported rarely

Toxicity

Data on nitazoxanide overdosage is not available . In studies in rodents and dogs, the oral LD50 was higher than 10,000 mg/kg. One-time oral doses of up to 4000 mg nitazoxanide have been given to healthy adult volunteers without severe adverse effects. Gastric lavage may be appropriate soon after oral administration if overdose occurs. Supportive and symptomatic treatment should also be administered .

According to previous studies , less than 1% of the patients age 12 years and older participating in clinical trials with NTZ suffered from the following adverse effects: Systemic: asthenia, fever, pain, allergic reaction, pelvic pain, back pain, chills, fever, flu-like syndrome. Central Nervous System: dizziness, somnolence, insomnia, tremor, hypesthesia. Gastrointestinal System: vomiting, dyspepsia, anorexia, flatulence, constipation, dry mouth, thirst. Urogenital System: discolored urine, dysuria, amenorrhea, metrorrhagia, kidney pain, edema labia. Metabolic & Nutrition: increased SGPT. Hemic & Lymphatic Systems: anemia, leukocytosis. Skin: rash, pruritus. Special Senses: eye discoloration, ear ache. Respiratory System: epistaxis, lung disease, pharyngitis. Cardiovascular System: tachycardia, syncope, hypertension. Muscular System: myalgia, leg cramps, spontaneous bone fracture.

Precaution

Nitazoxanide should be administrated with caution to patients with hepatic, renal and biliary disease.

Interaction

Nitazoxanide is highly bound to plasma protein (>99.9%). Therefore, caution should be used when administering Nitazoxanide concurrently with other highly plasma-protein bound drugs.

Food Interaction

• Take with food. Food improves oral bioavailability.

[Moderate] ADJUST DOSING INTERVAL: Food enhances the bioavailability of the pharmacologically active metabolite tizoxanide (desacetyl-nitazoxamide) from nitazoxanide administration.

According to the product labeling, administration of nitazoxanide tablets with food increases the area under the plasma concentration-time curve (AUC) of tizoxanide and tizoxanide glucuronide in plasma by almost 2-fold and the peak plasma concentration (Cmax) by almost 50%.

Administration of nitazoxanide oral suspension with food increases the AUC of tizoxanide and tizoxandie glucuronide by about 45% to 50% and the Cmax by less than 10%.

MANAGEMENT: Nitazoxanide tablets and oral suspension were administered with food in clinical trials and are recommended to be administered with food to ensure maximal drug levels in plasma.

Nitazoxanide Drug Interaction

Moderate: valproic acidUnknown: amphetamine / dextroamphetamine, amoxicillin / clavulanate, sulfamethoxazole / trimethoprim, mupirocin topical, celecoxib, ciprofloxacin, loratadine, sulfamethoxazole / trimethoprim, ubiquinone, duloxetine, meperidine, clonazepam, escitalopram, acetaminophen, bioflavonoids, cyanocobalamin, ascorbic acid, cholecalciferol, zinc sulfate

Nitazoxanide Disease Interaction

Moderate: diabetes, renal/liver disease

Elimination Route

The relative bioavailability of the suspension compared to the tablet was 70%. When administered with food the AUC and C_max increased by two-fold and 50%, respectively, for the tablet and 45 to 50% and ≤ 10%, respectively, for the oral suspension .

Half Life

7.3h

Clearance

Nitazoxanide is cleared in the urine and feces. The metabolite, tizoxanide, is also found in the urine, plasma, and breastmilk . The drug is not found unchanged in the urine .

Elimination Route

Tizoxanide is excreted in the urine, bile and feces, and tizoxanide glucuronide is excreted in urine and bile. Approximately 2/3 of the oral dose of nitazoxanide is excreted in the faeces and 1/3 in the urine .

Pregnancy & Breastfeeding use

Pregnancy category B. This drug should be used during pregnancy only if clearly needed.

Nursing mother: It is not known whether Nitazoxanide is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Nitazoxanide is administrated to a nursing woman.

Contraindication

Known hypersensitivity to Nitazoxanide or any other ingredient in the formulations

Special Warning

Paediatric Use: Safety and effectiveness of Nitazoxanide for Oral Suspension in paediatric patients less than one year of age have not been studied.

Impaired renal or hepatic function: The pharmacokinetics of Nitazoxanide in patients with impaired renal or hepatic function have not been studied. Therefore, Nitazoxanide must be administered with caution to patients with hepatic and biliary disease, to patients with renal disease and to patients with combined renal and hepatic disease.

Acute Overdose

Information on Nitazoxanide overdosage is not available. Single oral doses of up to 4000 mg Nitazoxanide have been administered to healthy adult volunteers without significant adverse effects.

Storage Condition

Store in a cool and dry place, away from light and moisture. Once reconstituted suspension should be used within 7 days.

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