Nitazoxanide 500mg Tablets
It is used to treat diarrhea caused by certain parasite infections.
Drug Class
Antiprotozoal
Pharmacologic Class
Thiazolide anti-infective
Pregnancy Category
Category B
FDA Approved
Nov 2002
DEA Schedule
Not Controlled
Overview
What is this medicine?
Nitazoxanide is an anti-parasitic medication used to treat diarrhea caused by certain infections, specifically Cryptosporidium and Giardia. It works by stopping the growth of these parasites in your body.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, take it exactly as directed by your doctor. Carefully read all the information provided with your prescription, and follow the instructions closely. It's recommended to take this medication with food.
Continue taking your medication as instructed by your doctor or healthcare provider, even if you start to feel better. This will help ensure that you receive the full benefits of the treatment.
Storing and Disposing of Your Medication
To maintain the quality and safety of your medication, store it at room temperature in a dry location, avoiding bathrooms. Keep all medications in a secure place, out of the reach of children and pets.
When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless specifically instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to inquire about drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To get the most benefit from your medication, take it exactly as directed by your doctor. Carefully read all the information provided with your prescription, and follow the instructions closely. It's recommended to take this medication with food.
Continue taking your medication as instructed by your doctor or healthcare provider, even if you start to feel better. This will help ensure that you receive the full benefits of the treatment.
Storing and Disposing of Your Medication
To maintain the quality and safety of your medication, store it at room temperature in a dry location, avoiding bathrooms. Keep all medications in a secure place, out of the reach of children and pets.
When disposing of unused or expired medication, do not flush it down the toilet or pour it down the drain unless specifically instructed to do so. Instead, consult with your pharmacist for guidance on the best disposal method. You may also want to inquire about drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take this medication with food to help your body absorb it better and reduce stomach upset.
- Complete the full course of treatment, even if you start feeling better, to ensure the infection is fully cleared.
- Practice good hygiene (e.g., handwashing) to prevent spread of infection.
Available Forms & Alternatives
Available Strengths:
Dosing & Administration
Adult Dosing
Standard Dose:
500 mg orally every 12 hours for 3 days
Dose Range:
500 - 500 mg
Condition-Specific Dosing:
Cryptosporidiosis:
500 mg orally every 12 hours for 3 days
Giardiasis:
500 mg orally every 12 hours for 3 days
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established for tablets; oral suspension (100 mg every 12 hours for 3 days) for 1-3 years.
Child:
Not established for tablets for children <12 years; oral suspension (200 mg every 12 hours for 3 days) for 4-11 years.
Adolescent:
500 mg orally every 12 hours for 3 days (for ages 12 years and older)
Dose Adjustments
Renal Impairment:
Mild:
No specific adjustment recommended
Moderate:
No specific adjustment recommended, use with caution due to limited data
Severe:
No specific adjustment recommended, use with caution due to limited data
Dialysis:
No specific adjustment recommended, use with caution due to limited data
Hepatic Impairment:
Mild:
No specific adjustment recommended
Moderate:
No specific adjustment recommended, use with caution due to limited data
Severe:
No specific adjustment recommended, use with caution due to limited data
Pharmacology
Mechanism of Action
Nitazoxanide is a thiazolide anti-infective. Its active metabolite, tizoxanide, is believed to interfere with the pyruvate ferredoxin oxidoreductase (PFOR) enzyme-dependent electron transfer reaction, which is essential for anaerobic energy metabolism in protozoa (e.g., Cryptosporidium parvum, Giardia lamblia). This inhibition disrupts the parasite's energy metabolism.
Pharmacokinetics
Absorption:
Bioavailability:
Not precisely determined, but rapidly absorbed. Food significantly increases absorption.
Tmax:
Tizoxanide: 1-4 hours; Tizoxanide glucuronide: 2-10 hours
FoodEffect:
Taking with food increases the AUC of tizoxanide by nearly 2-fold and Cmax by 50% compared to fasting conditions.
Distribution:
Vd:
Not available
ProteinBinding:
Tizoxanide: >99% (primarily to plasma proteins)
CnssPenetration:
Limited
Elimination:
HalfLife:
Tizoxanide: Approximately 1-2 hours; Tizoxanide glucuronide: Approximately 7-10 hours
Clearance:
Not available
ExcretionRoute:
Primarily fecal/biliary excretion (approximately 60% of dose as tizoxanide and tizoxanide glucuronide). Renal excretion accounts for a small percentage (approximately 30% as tizoxanide glucuronide).
Unchanged:
Negligible
Pharmacodynamics
OnsetOfAction:
Clinical improvement typically seen within 1-3 days of treatment initiation.
PeakEffect:
Not directly applicable as a single peak effect; relates to eradication of parasites.
DurationOfAction:
Duration of treatment is 3 days; sustained effect depends on successful eradication.
Safety & Warnings
Side Effects
Important Side Effects to Report to Your Doctor Immediately
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. Seek medical attention right away if you notice any of the following symptoms, which could be signs of a serious allergic reaction:
Rash
Hives
Itching
Red, swollen, blistered, or peeling skin with or without fever
Wheezing
Tightness in the chest or throat
Trouble breathing, swallowing, or talking
Unusual hoarseness
Swelling of the mouth, face, lips, tongue, or throat
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. Contact your doctor or seek medical help if you experience any of the following side effects or if they persist or bother you:
Headache
Stomach pain
Upset stomach
Change in urine color
Note: This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, consult your doctor for guidance.
Reporting Side Effects
To report side effects, you can:
Call your doctor for medical advice
Contact the FDA at 1-800-332-1088
Visit the FDA's MedWatch website at https://www.fda.gov/medwatch to report side effects online.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. Seek medical attention right away if you notice any of the following symptoms, which could be signs of a serious allergic reaction:
Rash
Hives
Itching
Red, swollen, blistered, or peeling skin with or without fever
Wheezing
Tightness in the chest or throat
Trouble breathing, swallowing, or talking
Unusual hoarseness
Swelling of the mouth, face, lips, tongue, or throat
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to discuss any concerns with your doctor. Contact your doctor or seek medical help if you experience any of the following side effects or if they persist or bother you:
Headache
Stomach pain
Upset stomach
Change in urine color
Note: This list is not exhaustive, and you may experience other side effects not mentioned here. If you have questions or concerns about side effects, consult your doctor for guidance.
Reporting Side Effects
To report side effects, you can:
Call your doctor for medical advice
Contact the FDA at 1-800-332-1088
Visit the FDA's MedWatch website at https://www.fda.gov/medwatch to report side effects online.
Seek Immediate Medical Attention If You Experience:
- Severe abdominal pain
- Persistent nausea or vomiting
- Rash or itching
- Signs of allergic reaction (e.g., swelling of face/throat, difficulty breathing)
- Unusual tiredness or weakness
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction and its symptoms.
If you are taking warfarin, as this may interact with the medication.
If the patient is a child under 12 years of age, as this medication is not recommended for children younger than 12 years old.
Additionally, this is not an exhaustive list of potential interactions. Therefore, it is crucial to discuss all of your:
Prescription and over-the-counter (OTC) medications
Natural products
Vitamins
* Health problems
with your doctor and pharmacist to ensure safe use. Before starting, stopping, or changing the dose of any medication, consult with your doctor to confirm it is safe to do so in conjunction with this medication.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances. Be sure to describe the allergic reaction and its symptoms.
If you are taking warfarin, as this may interact with the medication.
If the patient is a child under 12 years of age, as this medication is not recommended for children younger than 12 years old.
Additionally, this is not an exhaustive list of potential interactions. Therefore, it is crucial to discuss all of your:
Prescription and over-the-counter (OTC) medications
Natural products
Vitamins
* Health problems
with your doctor and pharmacist to ensure safe use. Before starting, stopping, or changing the dose of any medication, consult with your doctor to confirm it is safe to do so in conjunction with this medication.
Precautions & Cautions
It is essential to inform all of your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you are pregnant, planning to become pregnant, or are breast-feeding, be sure to discuss this with your doctor. You and your doctor will need to carefully weigh the benefits and risks of using this medication to ensure the best possible outcome for both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe gastrointestinal upset (nausea, vomiting, diarrhea)
- Abdominal pain
- Headache
What to Do:
There is no specific antidote for nitazoxanide overdose. Treatment should be symptomatic and supportive. Contact a poison control center immediately (Call 1-800-222-1222 in the US).
Drug Interactions
Moderate Interactions
- Warfarin (potential for increased INR, though not consistently reported; monitor INR if co-administered)
Unknown Interactions
- Highly protein-bound drugs (theoretical displacement, but not clinically significant for most)
Monitoring
Baseline Monitoring
Diagnosis of Cryptosporidiosis or Giardiasis
Rationale: Confirm appropriate indication for treatment.
Timing: Prior to initiation of therapy
Routine Monitoring
Clinical response (resolution of diarrhea, abdominal pain)
Frequency: Daily during treatment and post-treatment
Target: Resolution of symptoms
Action Threshold: Persistent or worsening symptoms may indicate treatment failure or alternative diagnosis.
Adverse effects (e.g., abdominal pain, nausea, headache)
Frequency: Daily during treatment
Target: Tolerable or absent
Action Threshold: Severe or intolerable side effects may require discontinuation.
Symptom Monitoring
- Resolution of diarrhea
- Resolution of abdominal cramps
- Resolution of nausea/vomiting
- Fever reduction
Special Patient Groups
Pregnancy
Nitazoxanide is classified as Pregnancy Category B. Animal reproduction studies have shown no evidence of harm to the fetus. However, there are no adequate and well-controlled studies in pregnant women. Use during pregnancy only if clearly needed and the potential benefits outweigh the potential risks.
Trimester-Specific Risks:
First Trimester:
No specific increased risk identified in animal studies; human data limited.
Second Trimester:
No specific increased risk identified in animal studies; human data limited.
Third Trimester:
No specific increased risk identified in animal studies; human data limited.
Lactation
Limited data are available on the presence of nitazoxanide or its metabolites in human milk. Due to the high protein binding of tizoxanide, transfer into milk is expected to be low. However, caution should be exercised when nitazoxanide is administered to a nursing woman. Consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for nitazoxanide and any potential adverse effects on the breastfed infant from nitazoxanide or from the underlying maternal condition.
Infant Risk:
Low risk, but use with caution due to limited human data.
Pediatric Use
Approved for use in pediatric patients 1 year of age and older. Dosing varies by age and weight, typically using the oral suspension for younger children and tablets for those 12 years and older. Safety and efficacy in children younger than 1 year have not been established.
Geriatric Use
No specific dose adjustment is recommended for elderly patients. However, elderly patients are more likely to have decreased renal or hepatic function, so caution should be exercised, and monitoring for adverse effects is prudent.
Clinical Information
Clinical Pearls
- Nitazoxanide is effective against Cryptosporidium parvum and Giardia lamblia, which are common causes of diarrheal illness.
- Always advise patients to take the medication with food to maximize absorption and minimize gastrointestinal side effects.
- The typical course of treatment is short (3 days), which can improve patient adherence.
- It is not effective against bacterial or viral causes of diarrhea.
- Consider stool testing to confirm parasitic infection before prescribing, especially in immunocompetent individuals.
Alternative Therapies
- Metronidazole (for Giardiasis)
- Tinidazole (for Giardiasis)
- Paromomycin (for Cryptosporidiosis, especially in immunocompromised patients)
- Albendazole (for Giardiasis, off-label)
Cost & Coverage
Average Cost:
$100 - $300 per 6 tablets (500mg)
Generic Available:
Yes
Insurance Coverage:
Tier 2 or 3 (varies by insurance plan)
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it occurred.