Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents with HIV

The information in the brief version is excerpted directly from the full-text guidelines. The brief version is a compilation of the tables and boxed recommendations.

Cystoisosporiasis (Formerly Isosporiasis)

Last Updated: September 10, 2015; Last Reviewed: June 26, 2019

Recommendations for Treating Isospora belli Infection
Treating Isospora belli Infection

General Management Considerations:

  • Fluid and electrolyte support in patients with dehydration (AIII)
  • Nutritional supplementation for malnourished patients (AIII)
Preferred Therapy for Acute Infection:
  • TMP-SMX (160 mg/800 mg) PO (or IV) QID for 10 days (AII), or
  • TMP-SMX (160 mg/800 mg) PO (or IV) BID for 7–10 days (BI)
  • One approach is to start with TMP-SMX (160 mg/800 mg) BID regimen first, and increase daily dose and/or duration (up to 3–4 weeks) if symptoms worsen or persist (BIII)
  • IV therapy for patients with potential or documented malabsorption
Alternative Therapy For Acute Infection (For Patients with Sulfa Intolerance):
  • Pyrimethamine 50–75 mg PO daily + leucovorin 10–25 mg PO daily (BIII), or
  • Ciprofloxacin 500 mg PO BID for 7 days (CI) 
Chronic Maintenance Therapy (Secondary Prophylaxis) 
(In Patients with CD4 Count <200/mm3)

Preferred Therapy:
  • TMP-SMX (160 mg/800 mg) PO 3 times weekly (AI)
Alternative Therapy:
  • TMP-SMX (160 mg/800 mg) PO daily (BIII), or 
  • TMP-SMX (320 mg/1600 mg) PO 3 times weekly (BIII), or
  • Pyrimethamine 25 mg PO daily + leucovorin 5–10 mg PO daily (BIII)
  • Ciprofloxacin 500 mg PO 3 times weekly (CI) as a second line alternative
Criteria for Discontinuation of Chronic Maintenance Therapy
  • Sustained increase in CD4 count >200 cells/mm3 for >6 months in response to ART and without evidence of active I. belli infection (BIII)

Key to Acronyms: ART = antiretroviral therapy; BID = twice daily; IV = intravenous; PO = orally; QID = four times a day; TMP-SMX = trimethoprim-sulfamethoxazole

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