Isosporiasis Medication

  • Author: Robert W Tolan Jr, MD; Chief Editor: Michael Stuart Bronze, MD   more...
 
Updated: Jun 29, 2011
 

Medication Summary

Isosporiasis does not respond well to most antibiotics used to treat diarrhea. Oral trimethoprim-sulfamethoxazole (TMP-SMZ) is the drug of choice. In patients who are intolerant to sulfonamides, pyrimethamine with folinic acid may be given for 2-4 weeks. Patients with AIDS may require long-term maintenance therapy with TMP-SMZ for suppression of I belli. Alternatively, pyrimethamine with sulfadoxine may be given.

Anecdotal case reports document improvement with albendazole, bismuth subsalicylate, diclazuril, furazolidone, metronidazole, and quinacrine; however, clinical trials are lacking.

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Antibiotics

Class Summary

Therapy must be comprehensive and cover all likely pathogens in the context of this clinical setting.

TMP-SMZ is the drug of choice because it is the best-studied and most readily available agent. An alternative for long-term prophylaxis is pyrimethamine with sulfadiazine or sulfadoxine (either of which should be accompanied by folinic acid). Studies have proposed the veterinary agent diclazuril as a possible drug of choice if further studies confirm its use and safety.

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Trimethoprim-sulfamethoxazole (Bactrim DS, Septra DS)

 

TMP-SMZ inhibits bacterial growth by inhibiting synthesis of dihydrofolic acid. It is the drug of choice and is curative in the immunocompetent host. It can be used for treatment and then ongoing prophylaxis in the immunocompromised host.

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Pyrimethamine (Daraprim)

 

Pyrimethamine is a folic acid antagonist that selectively inhibits plasmodial dihydrofolate reductase. It is the second drug of choice and is particularly useful for those who cannot tolerate sulfonamides. It can also be used for prophylaxis when combined with sulfadiazine or sulfadoxine. Administer it with folinic acid to prevent hematologic toxicities.

Diclazuril

 

Dicazuril is investigational in the United States. This benzene acetonitrile derivative is a veterinary antiparasitic that has shown good safety and efficacy in a small number of studies involving a small number of humans. Clinical trials have been completed for use in patients with AIDS and cryptosporidial-related diarrhea. It may become the drug of choice if further studies confirm these preliminary findings.

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Vitamins

Class Summary

Vitamins are used to correct folic acid deficiency resulting from use of folic acid antagonists.

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Leucovorin

 

A derivative of folic acid, which is used with folic acid antagonists such as sulfonamides and pyrimethamine.

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Contributor Information and Disclosures
Author

Robert W Tolan Jr, MD  Chief, Division of Allergy, Immunology and Infectious Diseases, The Children's Hospital at Saint Peter's University Hospital; Clinical Associate Professor of Pediatrics, Drexel University College of Medicine

Robert W Tolan Jr, MD is a member of the following medical societies: American Academy of Pediatrics, American Medical Association, American Society for Microbiology, American Society of Tropical Medicine and Hygiene, Infectious Diseases Society of America, Pediatric Infectious Diseases Society, Phi Beta Kappa, and Physicians for Social Responsibility

Disclosure: Novartis Honoraria Speaking and teaching

Coauthor(s)

Venkat R Minnaganti, MD  Consulting Staff, Department of Medicine, Winthrop University Hospital; Clinical Instructor, Department of Internal Medicine, Division of Infectious Disease, State University of New York School of Medicine at Stony Brook

Venkat R Minnaganti, MD is a member of the following medical societies: All India Ophthalmological Society, American College of Physicians, American Medical Association, American Society for Microbiology, and Infectious Diseases Society of America

Disclosure: Nothing to disclose.

Glenn Fennelly, MD, MPH  Director, Division of Infectious Diseases, Lewis M Fraad Department of Pediatrics, Jacobi Medical Center; Clinical Associate Professor of Pediatrics, Albert Einstein College of Medicine

Glenn Fennelly, MD, MPH is a member of the following medical societies: Pediatric Infectious Diseases Society

Disclosure: Nothing to disclose.

Specialty Editor Board

Klaus-Dieter Lessnau, MD, FCCP  Clinical Associate Professor of Medicine, New York University School of Medicine; Medical Director, Pulmonary Physiology Laboratory; Director of Research in Pulmonary Medicine, Department of Medicine, Section of Pulmonary Medicine, Lenox Hill Hospital

Klaus-Dieter Lessnau, MD, FCCP is a member of the following medical societies: American College of Chest Physicians, American College of Physicians, American Medical Association, American Thoracic Society, and Society of Critical Care Medicine

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD  Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Medscape Salary Employment

John W King, MD  Professor of Medicine, Chief, Section of Infectious Diseases, Director, Viral Therapeutics Clinics for Hepatitis, Louisiana State University Health Sciences Center; Consultant in Infectious Diseases, Overton Brooks Veterans Affairs Medical Center

John W King, MD is a member of the following medical societies: American Association for the Advancement of Science, American College of Physicians, American Federation for Medical Research, American Society for Microbiology, Association of Subspecialty Professors, Infectious Diseases Society of America, and Sigma Xi

Disclosure: emedicine $50.00 Author of chapter; MERCK None Other

Russell W Steele, MD  Head, Division of Pediatric Infectious Diseases, Ochsner Children's Health Center; Clinical Professor, Department of Pediatrics, Tulane University School of Medicine

Russell W Steele, MD is a member of the following medical societies: American Academy of Pediatrics, American Association of Immunologists, American Pediatric Society, American Society for Microbiology, Infectious Diseases Society of America, Louisiana State Medical Society, Pediatric Infectious Diseases Society, Society for Pediatric Research, and Southern Medical Association

Disclosure: Nothing to disclose.

Chief Editor

Michael Stuart Bronze, MD  Professor, Stewart G Wolf Chair in Internal Medicine, Department of Medicine, University of Oklahoma Health Science Center

Michael Stuart Bronze, MD is a member of the following medical societies: Alpha Omega Alpha, American College of Physicians, American Medical Association, Association of Professors of Medicine, Infectious Diseases Society of America, Oklahoma State Medical Association, and Southern Society for Clinical Investigation

Disclosure: Nothing to disclose.

References

  1. Woodcock HM. Notes on Protozoan parasites in the excreta. BMJ. 1915;2:709..

  2. Goodgame R. Emerging Causes of Traveler's Diarrhea: Cryptosporidium, Cyclospora, Isospora, and Microsporidia. Curr Infect Dis Rep. Feb 2003;5(1):66-73. [Medline].

  3. Sasaki M, Tanaka A, Nishimura T, Tsujikawa T, Andoh A, Ishizuka I, et al. A case of malabsorption syndrome caused by isosporiasis in an immunocompetent patient. J Gastroenterol. Jan 2004;39(1):88-9. [Medline].

  4. ten Hove RJ, van Lieshout L, Brienen EA, Perez MA, Verweij JJ. Real-time polymerase chain reaction for detection of Isospora belli in stool samples. Diagn Microbiol Infect Dis. Jul 2008;61(3):280-3. [Medline].

  5. Malik S, Samantaray JC, Bagga A, Das A. Refractory isosporiasis. Indian J Pediatr. May 2005;72(5):437-9. [Medline].

  6. Sorvillo FJ, Lieb LE, Seidel J, Kerndt P, Turner J, Ash LR. Epidemiology of isosporiasis among persons with acquired immunodeficiency syndrome in Los Angeles County. Am J Trop Med Hyg. Dec 1995;53(6):656-9. [Medline].

  7. Rowe JS, Shah SS, Motlhagodi S, Bafana M, Tawanana E, Truong HT, et al. An epidemiologic review of enteropathogens in Gaborone, Botswana: shifting patterns of resistance in an HIV endemic region. PLoS One. Jun 2 2010;5(6):e10924. [Medline]. [Full Text].

  8. DeHovitz JA, Pape JW, Boncy M, Johnson WD Jr. Clinical manifestations and therapy of Isospora belli infection in patients with the acquired immunodeficiency syndrome. N Engl J Med. Jul 10 1986;315(2):87-90. [Medline].

  9. Limson-Pobre RN, Merrick S, Gruen D, Soave R. Use of diclazuril for the treatment of isosporiasis in patients with AIDS. Clin Infect Dis. Jan 1995;20(1):201-2. [Medline].

  10. Fox LM, Saravolatz LD. Nitazoxanide: a new thiazolide antiparasitic agent. Clin Infect Dis. Apr 15 2005;40(8):1173-80. [Medline].

  11. Gilles HM, Hoffman PS. Treatment of intestinal parasitic infections: a review of nitazoxanide. Trends Parasitol. Mar 2002;18(3):95-7. [Medline].

 
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Oocyst of Isospora belli with 2 sporoblasts. From the Image Library, Division of Parasitic Diseases at the National Center for Infectious Diseases, Centers for Disease Control and Prevention (CDC), Atlanta, Georgia.
 
 
 
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