Resources for Health Professionals

Treatment

Trimethoprim-sulfamethoxazole (TMP-SMX), sold under the trade names Bactrim*, Septra*, and Cotrim*, is the medication of choice for Cystoisospora infection. The typical treatment regimen for adults is TMP 160 mg plus SMX 800 mg (one double-strength tablet), orally, twice a day, for 7 to 10 days.

Expert consultation is recommended if the patient is immunosuppressed, for example, has AIDS. Such patients may need to be treated longer and/or with higher daily doses. This is an example of an alternative regimen of TMP-SMX for adults: one double-strength tablet of TMP-SMX, orally, four times a day, for up to 3 or 4 weeks. Patients with AIDS also may need maintenance therapy (secondary prophylaxis) with TMP-SMX to prevent recurrence of symptomatic infection.

Only limited data are available regarding potential alternatives to TMP-SMX. Patients who are allergic to (or are intolerant of) TMP-SMX usually are treated with pyrimethamine. For adults, the typical daily dose of pyrimethamine is in the range of 50 to 75 mg. This daily dose is given orally, either once a day or divided into 2 separate doses. For example, 50 mg can be given in one dose, or 25 mg can be given twice a day. Pyrimethamine can suppress the bone marrow. To help prevent this, patients treated with pyrimethamine also take leucovorin, orally, in a daily dose in the range of 10 to 25 mg. Folinic acid is another name for leucovorin.

Ciprofloxacin is a second-line alternative. It is less effective than TMP-SMX but might have some activity against Cystoisospora. For adults, the treatment regimen is 500 mg, orally, twice a day, for 7 days.* Trimethoprim–sulfamethoxazole (TMP–SMX) is available for human use in the United States.

* Ciprofloxacin is available for human use in the United States.

* Use of trade names is for identification only and does not imply endorsement by the Public Health Service or by the U.S. Department of Health and Human Services.

References

Guidelines for Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents: Recommendations from CDC, the National Institutes of Health, and the HIV Medicine Association of the Infectious Diseases Society of America. MMWR. RR March 24, 2009 / 58(Early Release);1-198.
Verdier RI, Fitzgerald DW, Johnson WD, Jr, Pape JW. Trimethoprim-sulfamethoxazole compared with ciprofloxacin for treatment and prophylaxis of Isospora belli and Cyclospora cayetanensis infection in HIV-infected patients: a randomized, controlled trial. Ann Intern Med 2000;132:885-8.
Pape JW, Verdier RI, Johnson WD, Jr. Treatment and prophylaxis of Isospora belli infection in patients with the acquired immunodeficiency syndrome. N Engl J Med 1989;320:1044-7.
Weiss LM, Perlman DC, Sherman J, et al. Isospora belli infection: treatment with pyrimethamine. Ann Intern Med 1988;109:474-5.

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.

Trimethoprim–sulfamethoxazole

Trimethoprim–sulfamethoxazole (TMP–SMX) is in pregnancy category C. TMP–SMX should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. TMP-SMX should be avoided near-term because of the potential for hyperbilirubinemia and kernicterus in the newborn.

Pregnancy Category C: Either studies in animals have revealed adverse effects on the fetus (teratogenic or embryocidal, or other) and there are no controlled studies in women or studies in women and animals are not available. Drugs should be given only if the potential benefit justifies the potential risk to the fetus.

Trimethoprim–sulfamethoxazole (TMP–SMX) is excreted in breast milk. TMP–SMX generally is compatible with breastfeeding of healthy, full-term infants after the newborn period. However, TMP-SMX generally should be avoided by women when nursing infants who are premature, jaundiced, ill, or stressed, or who have glucose-6-phosphate dehydrogenase deficiency.

The safety of trimethoprim–sulfamethoxazole (TMP–SMX) in children has not been systematically evaluated. Use in children less than 2 months of age generally is not recommended.

Ciprofloxacin

Ciprofloxacin is in pregnancy category C. Data on the use of ciprofloxacin in pregnant women are limited, although the available evidence suggests that the risk for congenital anomalies is low. Ciprofloxacin should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Ciprofloxacin is excreted in breast milk. The American Academy of Pediatrics classifies ciprofloxacin as usually compatible with breastfeeding, whereas the World Health Organization recommends avoiding ciprofloxacin while breastfeeding. Ciprofloxacin should be used during lactation only if the potential benefit justifies the potential risk to the fetus.

Available evidence is conflicting regarding the potential for growth defects and arthropathies in exposed children. Use of ciprofloxacin in children requires assessment of potential risks and benefits.

Page last reviewed: May 21, 2020

Content source: Global Health, Division of Parasitic Diseases and Malaria