Nitazoxanide is a broad-spectrum antimicrobial and antiviral drug approved for the treatment of certain parasitic infections. It has also been investigated for use against a wide variety of viral and bacterial pathogens.
🔬 Overview:
Drug class: Thiazolide antiparasitic
Prodrug of: Tizoxanide (its active metabolite)
Brand name: Alinia (in the U.S.)
Formulations: Oral tablets or suspension
✅ Approved Uses (U.S. FDA):
Giardiasis (caused by Giardia lamblia)
Cryptosporidiosis (caused by Cryptosporidium parvum)
These are common protozoal infections, especially in children or immunocompromised individuals.
🦠 Antiviral & Investigational Uses:
Nitazoxanide has shown in vitro (lab-based) and some clinical activity against a wide range of viruses, including:
Influenza A & B
Hepatitis B and C
Norovirus
Rotavirus
SARS-CoV-2 (COVID-19)
Respiratory syncytial virus (RSV)
Its antiviral mechanism appears to involve:
Inhibition of viral maturation
Interference with host-regulated pathways (like interferon signaling)
Modulation of immune response
However, it is not yet approved for antiviral indications.
⚙️ Mechanism of Action:
Antiparasitic: Inhibits the enzyme pyruvate:ferredoxin oxidoreductase (PFOR), essential for anaerobic energy metabolism in protozoa.
Antiviral: Disrupts post-translational modification of viral proteins and may enhance host innate immune response.
⚠️ Side Effects:
Generally well tolerated
Most common: Nausea, abdominal pain, headache, discolored urine (harmless)
🌍 Global Relevance:
Nitazoxanide is used in many countries as an affordable treatment for parasitic diarrhea. Because of its broad-spectrum potential, it has gained interest as a repurposed drug in infectious disease research.
If you’re interested in its role in COVID-19, clinical trials have shown mixed results — promising lab data but inconsistent human trial outcomes. Would you like a summary of those studies?