nitazoxanid

Nitazoxanide, also spelled nitazoxanid, is a broad-spectrum antiparasitic and antiviral medication. It is a prodrug that is rapidly deacetylated in the body to tizoxanide, the pharmacologically active moiety. By inhibiting a pyruvate:ferredoxin oxidoreductase–dependent electron transfer pathway, tizoxanide disrupts energy metabolism in susceptible protozoa and some anaerobic bacteria, leading to impaired growth and death of the organisms.

Medical use: Nitazoxanide is approved in many jurisdictions for treatment of diarrhea caused by Giardia lamblia and Cryptosporidium parvum in adults and children. The recommended course is typically a three-day oral regimen; pediatric dosing is weight-based. It has also been studied for several other parasitic infections and, to a lesser extent, for viral infections such as influenza and SARS-CoV-2, though regulatory approvals for viral indications are limited and evidence varies.

Pharmacokinetics: After oral administration, nitazoxanide is absorbed and rapidly converted to tizoxanide; tizoxanide is the active metabolite. The drug is excreted mostly in urine and feces. Bioavailability improves with meals, and food can enhance absorption.

Safety: The most common adverse effects are gastrointestinal symptoms such as nausea, abdominal pain, diarrhea, and headache. Hypersensitivity and rare hepatic effects have been reported. Use in pregnancy and lactation should be guided by a healthcare provider.

Availability and history: Nitazoxanide is marketed under brand names such as Alinia and is available in tablet and oral suspension forms. It was developed in the 1990s and has since become a widely used antiparasitic with ongoing antiviral research.