Resources for Health Professionals
Three medications are used most often to treat Balantidium coli: tetracycline, metronidazole, and iodoquinol.
Tetracycline*: adults, 500 mg orally four times daily for 10 days; children ≥ 8 years old, 40 mg/kg/day (max. 2 grams) orally in four doses for 10 days. (Note: Tetracyclines are contraindicated in pregnancy and in children < 8 years old. Tetracycline should be taken 1 hour before or 2 hours after meals or ingestion of dairy products.)
Metronidazole*: adults, 500-750 mg orally three times daily for 5 days; children, 35-50 mg/kg/day orally in three doses for 5 days.
Iodoquinol*: adults, 650 mg orally three times daily for 20 days; children, 30-40 mg/kg/day (max 2 g) orally in three doses for 20 days. (Note: iodoquinol should be taken after meals.)
Nitazoxanide*: has been tried in small studies, which suggest some therapeutic benefit (adults, 500 mg orally twice daily for 3 days; children age 4-11 years old 200 mg orally twice daily for 3 days; children 1-3 years old 100 mg orally twice daily for 3 days).
*Not FDA-approved for this indication
* Tetracycline is available for human use in the United States.
* Metronidazole is available for human use in the United States.
* Iodoquinol is available for human use in the United States.
- Drugs for Parasitic Infections. Treatment Guidelines from the Medical Letter. Vol 8 (Suppl), 2010. The Medical Letter, Inc., New Rochelle, NY.
- Schuster FL, Ramirez-Avila L. Current world status of Balantidium coli. Clin Microbiol Rev. 2008 Oct;21(4):626-38.
- Hill DR, Nash TE. Intestinal flagellate and ciliate infections. In Tropical Infectious Diseases, Principals, Pathogens, and Practice. Guerrant RL, Walker DH, Weller PF, Eds. Saunders Elsevier, Philadelphia, PA, 2011, pp. 630.
- Abaza H, El-Zayadi AR, Kabil SM, Rizk H. Nitazoxanide in the treatment of patients with intestinal protozoan and helminthic infections: a report on 546 patients in Egypt. Curr Ther Res 1998;59:116-21.
This information is provided as an informational resource for licensed health care providers as guidance only. It is not intended as a substitute for professional judgment.
Tetracycline is in pregnancy category D. Tetracycline should not be used in pregnant women due to positive evidence of maternal and fetal risk. Use during pregnancy should be limited to instances when there are contraindications to the use of other appropriate antibiotics and the potential benefit justifies the known risk.
Tetracycline is excreted in breast milk. The American Academy of Pediatrics and the World Health Organization (WHO) both classify tetracycline as compatible with breast-feeding, although data on the use of tetracycline during lactation is limited. Tetracycline should be used during lactation only if the potential benefit of therapy to the mother justifies the known risk to the infant.
Tetracycline is contraindicated in children age 8 and younger as it may cause permanent discoloration of the teeth. The safety of intravenous tetracycline has not been established. Use of tetracycline in children age 8 and younger should be limited to instances when there are contraindications to the use of other appropriate antibiotics and the potential benefit justifies the known risk.
Metronidazole is in pregnancy category B. Data on the use of metronidazole in pregnant women are conflicting. The available evidence suggests use during pregnancy has a low risk of congenital anomalies. Metronidazole may be used during pregnancy in those patients who will clearly benefit from the drug, although its use should be weighed against any potential risks.
Pregnancy Category B: Either animal-reproduction studies have not demonstrated a fetal risk but there are no controlled studies in pregnant women or animal-reproduction studies have shown an adverse effect (other than a decrease in fertility) that was not confirmed in controlled studies in women in the first trimester (and there is no evidence of a risk in later trimesters).
Metronidazole is excreted in breast milk. The American Academy of Pediatrics classifies metronidazole as a drug for which the effect on nursing infants is unknown but may be of concern. The World Health Organization (WHO) advises to avoid metronidazole treatment in lactating women. Metronidazole should be used during lactation only if the potential benefit of therapy to the mother justifies the potential risk to the infant.
The safety of metronidazole in children has not been established. Metronidazole is listed as an antiamebic and antigiardiasis medicine on the WHO Model List of Essential Medicines for Children, intended for the use of children up to 12 years of age.
Oral iodoquinol has not been assigned a pregnancy category by the Food and Drug Administration. Data on the use of iodoquinol in pregnant women are limited, and risk to the embryo-fetus is unknown. Iodoquinol should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
It is not known whether iodoquinol is excreted in breast milk. Iodoquinol should be used with caution in breastfeeding women.
The safety of iodoquinol in children has not been established.