Use of dapsone in the treatment of Pneumocystis carinii pneumonia in a foal

Stuart C. Clark-Price, Judy H. Cox, Joshua T. Bartoe, Elizabeth G. Davis

Research output: Contribution to journalReview articlepeer-review


A 6-month-old male Quarter Horse was evaluated for chronic respiratory tract disease. Diagnostic investigations revealed pulmonary inflammation; Pneumocystis carinii was detected within macrophages. Lymphocyte subpopulation phenotyping and immunoglobulin concentration analysis were performed and results suggested immune suppression. Trimethoprim-sulfamethoxazole administration was initiated; the colt was discharged but was reexamined 8 days later because of profuse diarrhea and endotoxemia. Bacterial culture of feces recovered Salmonella spp resistant to trimethoprim-sulfamethoxazole, and a diagnosis of antimicrobial-associated colitis was made. Bilateral fibrinous hypopyon developed and was treated with topical medication and intracameral injections of human recombinant tissue plasminogen activator. Dapsone (3 mg/kg [1.4 mg/lb], PO, q 24 h; dose extrapolated from human data) was administered for treatment of P carinii pneumonia (56-day treatment period). The colt recovered from the pneumonia and diarrhea. Dapsone may be a useful adjunct to traditional treatment for P carinii pneumonia in horses or as a sole medication for horses that cannot tolerate other treatments.

Original languageEnglish (US)
Pages (from-to)407-410+371
JournalJournal of the American Veterinary Medical Association
Issue number3
StatePublished - Feb 1 2004
Externally publishedYes

ASJC Scopus subject areas

  • veterinary(all)


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