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Medically reviewed by Fedorchenko Olga Valeryevna, PharmD. Last updated on 26.06.2023
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Diarrhea Caused By Giardia lamblia or Cryptosporidium Parvum
Gintop for Oral Suspension (patients 1 year of age and older) and Gintop Tablets (patients 12 years and older) are indicated for the treatment of diarrhea caused by Giardia lamblia or Cryptosporidium parvum.
Limitations Of Use
Gintop for Oral Suspension and Gintop Tablets have not been shown to be effective for the treatment of diarrhea caused by Cryptosporidium parvum in HIV-infected or immunodeficient patients [ see Clinical Studies]
Recommended Dosage And Important Administration Instructions
Important Administration Instructions For Pediatric Patients 11 Years Of Age Or Younger
Gintop tablets should not be administered to pediatric patients 11 years of age or younger because a single tablet contains a greater amount of nitazoxanide than the recommended dosing in this pediatric age group.
Table 1: Recommended Dos age
| Age | Dosage | Duration |
| 1-3 years | 5 mL of Gintop for Oral suspension (100 mg nitazoxanide) taken orally every 12 hours with food | - |
| 4-11 years | 10 mL of Gintop for Oral Suspension (200 mg nitazoxanide) taken orally every 12 hours with food | 3 Days |
| 12 years and older | One Gintop Tablet (500 mg nitazoxanide) taken orally every 12 hours with food or 25 mL of Gintop for Oral Suspension (500 mg nitazoxanide) taken orally every 12 hours with food |
Directions For Mixing Gintop For Oral Suspension
Reconstitute Gintop for Oral Suspension as follows:
- Measure 48 mL of water for preparation of the 100 mg/5 mL suspension
- Tap bottle until all powder flows freely.
- Add approximately one-half of the 48 mL of water required for reconstitution and shake vigorously to suspend powder.
- Add remainder of water and again shake vigorously
Keep container tightly closed, and shake the suspension well before each administration. The reconstituted suspension may be stored for 7 days at room temperature, after which any unused portion must be discarded.
Hypersensitivity
Gintop Tablets and Gintop for Oral Suspension are contraindicated in patients with a prior hypersensitivity to nitazoxanide or any other ingredient in the formulations.
WARNINGS
Included as part of the PRECAUTIONS section.
PRECAUTIONS
Nonclinical Toxicology
Carcinogenesis, Mutagenesis, Impairment Of Fertility
Carcinogenesis
Long-term carcinogenicity studies have not been conducted.
Mutagenesis
Nitazoxanide was not genotoxic in the Chinese hamster ovary (CHO) cell chromosomal aberration assay or the mouse micronucleus assay. Nitazoxanide was genotoxic in one tester strain (TA100) in the Ames bacterial mutation assay.
Impairment Of Fertility
Nitazoxanide did not adversely affect male or female fertility in the rat at 2400 mg/kg/day (approximately 20 times the clinical adult dose adjusted for body surface area).
Use In Specific Populations
Pregnancy
Risk Summary
There are no data with Gintop in pregnant women to inform a drug-associated risk. No teratogenicity or fetotoxicity was observed in animal reproduction studies with administration of nitazoxanide to pregnant rats and rabbits during organogenesis at exposure 30 and 2 times, respectively, the exposure at the maximum recommended human dose of 500 mg twice daily based on body surface area (BSA). In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.
Data
Animal Data
Nitazoxanide was administered orally to pregnant rats at doses of 0, 200, 800 or 3200 mg/kg/day on gestation days 6 to 15. Nitazoxanide produced no evidence of systemic maternal toxicity when administer once daily via oral gavage to pregnant female rats at levels up to 3200 mg/kg/day during the period of organogenesis.
In rabbits, nitazoxanide was administered at doses of 0, 25, 50, or 100 mg/kg/day on gestation days 7 to 20. Oral treatment of pregnant rabbits with nitazoxanide during organogenesis resulted in minimal maternal toxicity and no external fetal anomalies.
Lactation
Risk Summary
No information regarding the presence of nitazoxanide in human milk, the effects on the breastfed infant, or the effects on milk production is available. The development and health benefits of breastfeeding should be considered along with the mother's clinical need for Gintop and any potential adverse effects on the breastfed infant from Gintop or from the underlying maternal condition.
Pediatric Use
The safety and efficacy of Gintop for Oral Suspension for the treatment of diarrhea caused by G. lamblia or C. parvum in pediatric patients 1 to 11 years of age has been established based on three (3) randomized, controlled studies with 104 pediatric subjects treated with Gintop for Oral Suspension 100 mg/5 mL. Furthermore, the safety and efficacy of Gintop for Oral Suspension for the treatment of diarrhea caused by G. lamblia or C. parvum in pediatric patients 12 to 17 years of age has been established based on two (2) randomized controlled studies with 44 pediatric subjects treated with Gintop for Oral Suspension 100 mg/5 mL. [Clinical Studies]
The safety and efficacy of Gintop Tablets for the treatment of diarrhea caused by G. lamblia or C. parvum in pediatric patients 12 to 17 years of age has been established based on three (3) randomized controlled studies with 47 pediatric subjects treated with Gintop Tablets 500 mg.
A single Gintop Tablet contains a greater amount of nitazoxanide than is recommended for use in pediatric patients 11 years or younger..
Safety and efficacy of Gintop for Oral Suspension in pediatric patients less than one year of age has not been studied.
Geriatric Use
Clinical studies of Gintop Tablets and Gintop for Oral Suspension did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy in elderly patients should be considered when prescribing Gintop Tablets and Gintop for Oral Suspension.
Renal And Hepatic Impairment
The pharmacokinetics of nitzoxanide in patients with compromised renal or hepatic function has not been studied.
HIV-Infected Or Immunodeficient Patients
Gintop Tablets and Gintop for Oral Suspension have not been studied for the treatment of diarrhea caused by G. lamblia in HIV-infected or immunodeficient patients. Gintop Tablets and Gintop for Oral Suspension have not been shown to be superior to placebo for the treatment of diarrhea caused by C. parvum in HIV-infected or immunodeficient patients [ see Clinical Studies]
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reactions rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
The safety of Gintop was evaluated in 2177 HIV-uninfected subjects 12 months of age and older who received Gintop Tablets or Gintop for Oral Suspension at the recommended dose for at least three days. In pooled controlled clinical trials involving 536 HIV-uninfected subjects treated with Gintop Tablets or Gintop for Oral Suspension, the most common adverse reactions were abdominal pain, headache, chromaturia and nausea (≥2%).
Safety data were analyzed separately for 280 HIV-uninfected subjects ≥12 years of age receiving Gintop at the recommended dose for at least three days in 5 placebo-controlled clinical trials and for 256 HIV-uninfected subjects 1 through 11 years of age in 7 controlled clinical trials. There were no differences between the adverse reactions reported for Gintop-treated subjects based upon age.
Postmarketing Experience
The following adverse reactions have been identified during post approval use of Gintop. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. The following is a list of adverse reactions spontaneously reported with Gintop Tablets which were not included in clinical trial listings:
Gastrointestinal disorders: diarrhea, gastroesophageal reflux disease
Nervous System disorders: dizziness
Respiratory, thoracic and mediastinal disorders: dyspnea
Skin and subcutaneous tissue disorders: rash, urticaria
Limited information on nitazoxanide overdosage is available. Single oral doses of up to 4000 mg nitazoxanide have been administered to healthy adult volunteers without significant adverse effects. In the event of overdose, gastric lavage may be appropriate soon after oral administration. Patients should be observed and given symptomatic and supportive treatment. There is no specific antidote for overdose with Gintop. Because tizoxanide is highly protein bound ( > 99.9%), dialysis is unlikely to significantly reduce plasma concentrations of the drug.
Absorption
Single Dosing
Following oral administration of Gintop Tablets or Oral Suspension, the parent drug, nitazoxanide, is not detected in plasma. The pharmacokinetic parameners of the metabolites, tizoxanide and tizoxanide glucuronide are shown in Tables 2 and 3 below.
Table 2: Mean (+/- SD) plasma pharmacokinetic parameters of tizoxanide and tizoxanide glucuronide following administration of a single dose of one 500 mg Gintop Tablet with food to subjects ≥12 years of age
| Age | Tizoxanide | Tizoxanide Glucuronide | ||||
| Cmax (μg/mL) | *Tmax (hr) | AUC t (μg•hr/mL) | C max (μg/mL) | Tmax (hr) | AUC t (μg•hr/mL) | |
| 12 - 17 years | 9.1 (6.1) | 4.0 (1-4) | 39.5 (24.2) | 7.3 (1.9) | 4.0 (2-8) | 46.5 (18.2) |
| > 18 years | 10.6 (2.0) | 3.0 (2-4) | 41.9 (6.0) | 10.5 (1.4) | 4.5 (4-6) | 63.0 (12.3) |
| *Tmax is given as a Mean (Range) |
Table 3: Mean (+/-SD) plasma pharmacokinetic of tizoxanide and tizoxanide glucuronide parameter values following administration of single dose of Gintop for Oral Suspension with food to subjects ≥1year of age
| Age | Dose | Tizoxanide | Tizoxanide Glucuronide | ||||
| max (μg/mL) | *Tmax (hr) | AUC t (μg•hr/mL) | C max (μg/mL) | *Tmax (hr) | AUC inf (μg•hr/mL) | ||
| 1-3 years | 100 mg | 3.11 (2.0) | 3.5 (2-4) | 11.7 (4.46) | 3.64 (1.16) | 4.0 (3-4) | 19.0 (5.03) |
| 4-11 years | 200 mg | 3.00 (0.99) | 2.0 (1-4) | 13.5 (3.3) | 2.84 (0.97) | 4.0 (2-4) | 16.9 (5.00) |
| > 18 years | 500 mg | 5.49 (2.06) | 2.5 (1-5) | 30.2 (12.3) | 3.21 (1.05) | 4.0 (2.56) | 22.8 (6.49) |
| *Tmax is given as a Mean (Range) |
Multiple Dosing
Following oral administration of a single Gintop Tablet every 12 hours for 7 consecutive days, there was no significant accumulation of nitazoxanide metabolites tizoxanide or tizoxanide glucuronide detected in plasma.
Bioavailability
Gintop for Oral Suspension is not bioequivalent to Gintop Tablets. The relative bioavailability of the suspension compared to the tablet was 70%.
When Gintop Tablets are administered with food, the AUCt of tizoxanide and tizoxanide glucuronide in plasma is increased almost two-fold and the Cmax is increased by almost 50%.
When Gintop for Oral Suspension was administered with food, the AUCt of tizoxanide and tizoxanide glucuronide increased by about 45-50% and the Cmax increased by ≥ 10%.
Gintop Tablets and Gintop for Oral Suspension were administered with food in clinical trials and hence they are recomended to be administered with food
Distribution
In plasma, more than 99% of tizoxanide is bound to proteins.
Elimination
Metabolism
Following oral administration in humans, nitazoxanide is rapidly hydrolyzed to an active metabolite, tizoxanide (desacetyl-nitazoxanide). Tizoxanide then undergoes conjugation, primarily by glucuronidation.
Excretion
Tizoxanide is excreted in the urine, bile and feces, and tizoxanide glucuronide is excreted in urine and bile. Approximately two-thirds of the oral dose of nitazoxanide is excreted in the feces and one-third in the urine.
