Clinical Care of Crypto

Key points

  • The Food and Drug Administration (FDA) approved nitazoxanide to treat diarrhea caused by Cryptosporidium in people with healthy immune systems.
  • The effectiveness of nitazoxanide to treat Cryptosporidium in people with weakened immune systems is unclear.
Health care provider talking to child and mother.

Treatment options

In 2002, the U.S. Food and Drug Administration (FDA) licensed nitazoxanide (Alinia®, Romark Laboratories, Tampa, FL, USA) for the treatment of cryptosporidiosis in children with healthy immune systems aged 1–11 years. In 2004, nitazoxanide was also licensed for people with healthy immune systems aged 12 years and older. It can now be prescribed for all patients with healthy immune systems aged ≥1 years.

Treatment recommendations

Treating patients with weakened immune systems‎

Nitazoxanide is not approved to treat patients with weakened immune systems. Nitazoxanide oral suspension and nitazoxanide tablets have not been shown to be superior to placebo for the treatment of diarrhea caused by Cryptosporidium in patients who are HIV-infected or who have weakened immune systems. The National Institutes of Health (NIH) provides recommendations for treating cryptosporidiosis in HIV-infected children and in HIV-infected adults and adolescents.

In people with healthy immune systems, 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.

A single tablet contains a greater amount of nitazoxanide than recommended for pediatric dosing, and thus, should not be used for patients ages <11 years.

Dosage guidelines for people with healthy immune systems

Dosage for treatment of diarrhea caused by G. lamblia or C. parvum
Age Dosage Duration
1-3 years 5 mL of ALINIA for Oral Suspension (100 mg nitazoxanide) every 12 hours with food 3 days
4-11 years 10 mL of ALINIA for Oral Suspension (200 mg nitazoxanide) every 12 hours with food
12 years and older One ALINIA Tablet (500 mg nitazoxanide) every 12 hours with food or 25 mL of ALINIA for Oral Suspension (500 mg nitazoxanide) every 12 hours with food

Dosage guidelines also available on FDA's website.

Treatment efficacy

  • Clinical cure (resolution of diarrhea) rates range from 72–88%.
  • Parasitologic cure (Crypto undetectable in stool) rates range from 60–75%.

Healthcare professionals might consider retesting 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 can also represent reinfection or causes other than Cryptosporidium.

Nitazoxanide appears to be well tolerated and different treatment regimens have been used for a variety of infections. In patients with healthy immune systems, cryptosporidiosis has been treated with multiple 3-day courses of nitazoxanide; 7-day courses have also been used in early studies of cryptosporidiosis and other parasitic infections.

Precautions to prevent further spread

Cryptosporidium causes over half of the waterborne disease outbreaks associated with public swimming pools, hot tubs, and splash pads. Cryptosporidium's chlorine resistance and documented excretion for weeks after resolution of symptoms has led CDC and The American Academy of Pediatrics to recommend that patients refrain from swimming until two weeks after resolution of their symptoms. Following this recommendation will help prevent Cryptosporidium from being transmitted through recreational water.

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