Nidor500 mg

Nidor is an antiprotozoal medicine used to treat certain parasitic causes of diarrhea.

Established / FDA-approved uses

• Treatment of diarrhea caused by Giardia lamblia (giardiasis) in patients 1 year of age and older.
• Treatment of diarrhea caused by Cryptosporidium parvum (cryptosporidiosis) in patients 1 year of age and older who are otherwise immunocompetent. Efficacy has not been established in patients who are immunocompromised (for example, patients with HIV/AIDS).

Regional / additional labeling

• In some regional labels (including Bangladesh), Nidor is also indicated for diarrhea/dysentery caused by Entamoeba histolytica, based on local regulatory approval and clinical experience rather than US FDA labeling.

Off-label / investigational use

Nidor has also been studied off-label for other intestinal parasitic infections and, during the COVID-19 pandemic, was investigated as a possible antiviral against certain viral gastroenteritis and respiratory viruses; evidence for these uses is limited and inconsistent, and such use should only occur under a physician's guidance.

Each tablet or reconstituted oral suspension of Nitazoxanide contains nitazoxanide as the active pharmaceutical ingredient.

• Tablet: Nitazoxanide 500 mg
• Powder for oral suspension: Nitazoxanide 100 mg per 5 mL after reconstitution

Inactive ingredients vary by manufacturer/brand; refer to the specific product package insert for excipient details.

Nidor is a synthetic thiazolide antiparasitic (antiprotozoal) agent. It is used orally to treat intestinal infections caused by susceptible protozoan parasites, most notably Giardia lamblia and Cryptosporidium parvum.

Nidor is available as film-coated tablets and as a powder for oral suspension, and is typically given as a short 3-day course with food.

Nidor belongs to the thiazolide antiprotozoal / antiparasitic class of medicines. It is not an antibiotic in the classical antibacterial sense, but it is an antimicrobial agent active against certain protozoa.

Nitazoxanide and its active circulating metabolite, tizoxanide, interfere with the anaerobic energy metabolism of susceptible protozoa by inhibiting the pyruvate:ferredoxin oxidoreductase (PFOR) enzyme-dependent electron transfer reaction, which is essential for anaerobic energy metabolism in these organisms.

After oral administration, Nitazoxanide is rapidly hydrolyzed to tizoxanide, which is further conjugated to tizoxanide glucuronide. Tizoxanide is highly (>99.9%) bound to plasma proteins. Absorption is enhanced when Nitazoxanide is taken with food. Tizoxanide is excreted in urine, bile, and feces, and tizoxanide glucuronide is excreted primarily in urine and bile.

• Take Nidor orally with food to enhance absorption.
• Shake the reconstituted oral suspension well before each use; measure the dose with an appropriate oral dosing device.
• Swallow tablets whole; tablets are approved for patients 12 years and older.
• Complete the full prescribed course even if symptoms improve before finishing, unless advised otherwise by a physician.

The active metabolite of Nidor (tizoxanide) is highly bound to plasma protein (>99.9%). Caution is advised when Nidor is given together with other highly plasma-protein-bound drugs with a narrow therapeutic index, such as warfarin, because of the theoretical potential for displacement interactions; monitor for changes in anticoagulant effect (e.g., INR) if co-administered.

Nidor is not expected to significantly inhibit or induce major cytochrome P450 enzymes based on available data, so clinically significant CYP-mediated drug interactions are not well established. Always inform your physician or pharmacist of all other medications, including over-the-counter drugs and supplements, before starting Nidor.

Most adverse effects associated with Nidor are mild and gastrointestinal in nature.

Common

• Abdominal pain
• Diarrhea
• Headache
• Nausea
• Vomiting (more frequently reported in children)

Less common

• Dyspepsia, flatulence, anorexia
• Dizziness
• Discoloration of urine (harmless)

Seek medical attention promptly for signs of an allergic reaction (rash, itching, swelling, severe dizziness, trouble breathing) or for persistent, severe, or bloody diarrhea, high fever, or signs of dehydration while taking Nidor, as these may indicate a different or more serious underlying condition.

Pregnancy: Animal reproduction studies with Nidor at doses higher than the human dose have not shown evidence of fetal harm, but there are no adequate and well-controlled studies in pregnant women. Nidor should be used during pregnancy only if clearly needed and if the potential benefit justifies the potential risk to the fetus; consult a physician before use.

Lactation: It is not known whether Nidor or its metabolites are excreted in human breast milk. Caution should be exercised, and a physician should be consulted, before using Nidor while breastfeeding.

• Use Nidor with caution in patients with hepatic or renal impairment, as pharmacokinetics in these populations have not been formally studied.
• The efficacy of Nidor for cryptosporidiosis has not been established in immunocompromised patients (for example, those with HIV/AIDS); consult a specialist for alternative or additional management in these patients.
• Discontinue Nidor and seek prompt medical attention if diarrhea worsens, becomes bloody, or is accompanied by high fever or signs of dehydration, as this may indicate a condition other than, or in addition to, the one being treated.
• Take Nidor exactly as prescribed by your physician; do not stop, extend, skip doses, or share this medicine with others without medical advice.
• The oral suspension of Nidor contains sugar (sucrose); use caution in patients with diabetes mellitus.

Limited data are available on overdose with Nidor; single doses up to 4000 mg have been given to healthy volunteers without serious adverse effects in clinical studies, but this does not mean higher doses are safe for all patients.

If an overdose of Nidor is suspected, seek immediate medical attention or contact a poison control center / emergency services. Treatment of overdose is supportive and symptomatic; there is no specific antidote.

Store tablets at room temperature (below 30°C), away from light and moisture. For the oral suspension, once Nidor powder has been reconstituted with water, store the suspension at room temperature (do not freeze) and discard any unused portion after 7 days. Keep out of reach of children.

Renal impairment

The pharmacokinetics of Nidor in patients with renal impairment have not been studied; use with caution and monitor closely.

Hepatic impairment

The pharmacokinetics of Nidor in patients with hepatic impairment have not been studied; use with caution and monitor closely.

Elderly

Clinical studies of Nidor did not include sufficient numbers of patients aged 65 and over to determine whether they respond differently from younger patients; dose selection should be cautious.

Immunocompromised patients

Efficacy of Nidor for cryptosporidiosis has not been established in HIV-positive or other immunocompromised patients.

Pregnancy and lactation

See Pregnancy and Lactation section above.

The standard course of Nidor for approved indications (giardiasis and cryptosporidiosis) is 3 days, taken twice daily with food. Your physician may adjust the duration based on clinical response; do not extend or shorten the course without medical advice.

To reconstitute the oral suspension of Nidor: tap the bottle to loosen the powder, then add the amount of water indicated on the label in two portions, shaking well after each addition, to make a final volume that provides 100 mg of Nidor per 5 mL. Shake well before each use. Store the reconstituted suspension at room temperature, do not freeze, and discard any unused portion after 7 days.

Nitazoxanide is classified as a thiazolide antiprotozoal agent (nitrothiazolyl-salicylamide derivative), a class of synthetic antimicrobials active against certain anaerobic protozoa and, to a lesser extent, some anaerobic bacteria and helminths.

Nitazoxanide and its active metabolite tizoxanide inhibit the pyruvate:ferredoxin oxidoreductase (PFOR) enzyme-dependent electron transfer reaction that is essential for anaerobic energy metabolism in susceptible protozoa such as Giardia lamblia and Cryptosporidium parvum. Interference with this energy-generating pathway leads to parasite death. See Pharmacology for additional detail.

B

Nidor oral suspension is approved for use in children 1 year of age and older for the treatment of diarrhea due to Giardia lamblia or Cryptosporidium parvum. Tablets are approved for patients 12 years and older.

The safety and efficacy of Nidor in children younger than 1 year of age have not been established.