Nitazoxanide

Nitazoxanide is a drug that fights infections by protozoa other than malaria. It treats diarrhea caused by Cryptosporidium parvum and Giardia lamblia. In children over one year of age, adolescents, and adults, nitazoxanide reduces the duration of diarrhea and helps eliminate the protozoa from the body.

Romark Laboratories developed and markets nitazoxanide, which has the brand names Alinia or Annita and was approved for use in the United States in 2002.

The chemical structure of nitazoxanide. Source: Wikimedia Commons

Uses/Indications

Nitazoxanide is used to treat diarrhea caused by the protozoa Cryptosporidium parvum and Giardia lamblia. It may also be used to treat amebiasis caused by Entamoeba histolytica. Protozoa are microscopic, single-celled organisms such as amoebas. Nitazoxanide is used in children over one year of age, in adolescents, and in adults.

Infection with Cryptosporidium parvum causes cryptosporidiosis, and infection with Giardia lamblia causes giardiasis. Giardia lamblia are the most common intestinal protozoa in the United States. Usually the infections caused by these protozoa resolve without treatment in individuals with healthy immune systems. Sometimes, however, the diarrhea can be chronic. The protozoa contaminate food and water and can be spread by hands. In fact, Giardia lamblia was the most common cause of water-borne diarrhea in the United States between 1978 and 1991. Nitazoxanide is the only drug available in the United States to treat cryptosporidiosis. It is also only the third drug to be approved for the treatment of giardiasis.

Nitazoxanide is also being investigated as a treatment for diarrhea caused by other infections and as a treatment for hepatitis. Some physicians are already using it to treat diarrhea caused by Clostridium difficile bacteria.

How Nitazoxanide Is Taken

Nitazoxanide is available as a tablet or as a syrup. The tablets are 500 mg. The strawberry-flavored syrup contains 100 mg nitazoxanide in 5 ml of suspension. Tablets are typically given to adolescents (12 years of age or older) and adults, whereas children between 1 and 12 years old are given the syrup.

Each dose of nitazoxanide should be taken with food. The recommended dosage regimens are as follows:

• Children 1-3 years of age: 5 ml syrup every 12 hours for 3 days
• Children 4-11 years of age: 10 ml of syrup every 12 hours for 3 days
• Adolescents over 12 years of age and adults: 500 mg tablet or 25 ml of syrup every 12 hours for 3 days

A photomicrograph of Giardia protozoan (center) Magnification: 1000X

How Nitazoxanide Works

Nitazoxanide inhibits energy production in Cryptosporidium parvum and Giardia lamblia. Without energy to maintain cellular processes, the protozoa cannot grow and are excreted.

How the Body Affects Nitazoxanide

Nitazoxanide itself is not active. Instead, the liver converts it into two active forms. The concentrations of these forms reach a peak in the blood after 1-4 hours. Approximately 30% more of the tablet is absorbed relative to the syrup. Food increases absorption of both the tablets and syrup, but it has greater effects on the tablet. The two active forms of nitazoxanide are excreted in feces, urine, and into the bile.

Side Effects

These side effects have been reported in patients 12 years of age or older receiving nitazoxanide:

• abdominal pain
• diarrhea
• headache
• nausea
• greenish tint of urine

Similar side effects are seen in children between 1 year and 12 years of age, except that some children experience vomiting. Usually the side effects are mild and transient.

Risks and Precautions

• Nitazoxanide should be used with caution in individuals with kidney or liver problems, and in those with impaired liver or gall bladder function.

• Diabetics should be aware that the syrup contains 1.48 grams of sugar.

Nitazoxanide is unlikely to interact with other drugs. As with all medications, however, physicians should be aware of other drugs and supplements a patient is taking.

Clinical Trials

Nitazoxanide helps to clear the protozoa from the body and reduce the duration of diarrhea. Diarrhea is usually resolved within three or four days of starting nitazoxanide. However, nitazoxanide has not been proven effective for treating diarrhea caused by Cryptosporidium parvum in patients with HIV/AIDS or in patients with a suppressed immune system.

A study performed in Egypt evaluated the effectiveness of nitazoxanide in individuals 12 years of age or older.^[1] Patients with diarrhea caused by Cryptosporidium were given nitazoxanide in syrup (25 ml) or tablet (500 mg) or a placebo for three days. Four days after stopping treatment, 96% of patients given the nitazoxanide tablets and 87% given the syrup improved. The parasite was cleared from 93% of patients treated with nitazoxanide tablets and 90% of those who were given the syrup. Another study in Egypt included patients 1-11 years of age with the adolescents and adults.^[2] After three days of treatment with nitazoxanide, diarrhea resolved in 80% of patients, whereas diarrhea resolved in 41% of patients given placebo.

Nitazoxanide also prevents mortality due to diarrhea.^[3] Nitazoxanide resolved diarrhea in 56% of Zambian children with Cryptosporidium parvum. None of the children treated with nitazoxanide had died, wheras 4% of the plcebo-treated children had died.

Nitazoxanide Clinical Trials can be found here

References

1. ↑ Rossignol JF, Kabil SM, el-Gohary Y, et al. Effect of nitazoxanide in diarrhea and enteritis caused by Cryptosporidium species. Clin Gastroenterol Hepatol 2006;4:320-4.
2. ↑ Rossignol JF, Ayoub A, Ayers MS. Treatment of diarrhea caused by Cryptosporidium parvum: a prospective randomized, double-blind, placebo-controlled study of Nitazoxanide. J Infect Dis 2001;184:103-6.
3. ↑ Amadi B, Mwiya M, Musuku J, et al. Effect of nitazoxanide on morbidity and mortality in Zambian children with cryptosporidiosis: a randomized controlled trial. Abstract. Lancet 2002;360:1375-80.

External Links

Romark Laboratories: Alinia Main Page

Drugs.com: Alinia

PRNewswire: Romark Completes Clinical Study of Alinia in Treating Clostridium Difficile-Associated Disease

FDA Consumer Information: Alinia