Nitazoxanide

In 2004, the FDA licensed nitazoxanide for all persons ≥ 1 year of age. It had previously been licensed in 2002 for only children aged 1-11 years.

Nitazoxanide oral suspension (100 mg/5ml; patients ≥ 1 year of age) and Nitazoxanide tablets (500 mg; patients ≥ 12 years of age) are indicated for the treatment of diarrhea caused by Cryptosporidium.

Clinical cure (resolution of diarrhea) rates range from 72-88% ¹. Parasitologic cure (no Cryptosporidium detected in stool) rates range from 60-75% ¹. Parasitologic cure rate was a key consideration in developing prevention recommendations that ask people to refrain from swimming for 2 weeks after resolution of symptoms. Retesting of treated persons is not considered necessary.

It may take up to 5 days for diarrhea to resolve in approximately 80% of patients ⁴. Because of this and the lower parasitologic cure rate, CDC still recommends that all infected persons, including those who have completed treatment, do not swim for 2 weeks after resolution of symptoms. It is critical that this recommendation is followed to prevent the spread of this chlorine-resistant parasite through public swimming pools and other aquatics venues.

Healthcare professionals might consider re-testing stool at least 1 week after the last dose of nitazoxanide only if symptoms do not resolve. In such cases, longer courses of treatment might be needed. Persistent symptoms may also represent re-infection or other causes of illness besides cryptosporidiosis.

Nitazoxanide appears to be well tolerated and different treatment regimens have been used for a variety of infections. Immunocompetent persons with cryptosporidiosis have been treated with multiple 3-day courses of nitazoxanide ⁵. Seven-day courses have also been used in early studies for cryptosporidiosis and other parasitic infections ^{6, 7}. AIDS patients with Cryptosporidium-associated diarrhea received the drug for 28 days ⁸.

Nitazoxanide has been approved for treatment of diarrhea caused by Cryptosporidium in people with healthy immune systems. It is presently not approved to treat immunodeficient persons because nitazoxanide oral suspension and nitazoxanide tablets have not been shown to be superior to placebo for the treatment of diarrhea caused by Cryptosporidium in HIV-infected or immunodeficient patients ¹.

Cryptosporidium now causes over half of the reported waterborne disease outbreaks associated with swimming in chlorinated public swimming pools ⁹. Cryptosporidium’s chlorine resistance and documented excretion for weeks after resolution of symptoms has led CDC and The American Academy of Pediatrics ¹⁰ to recommend that all persons refrain from swimming until 2 weeks after resolution of symptoms.