Utilization of Nitazoxanide for the Empiric Treatment of Diarrhea of Unknown Etiology

Abstract

Purpose: Diarrhea of unknown etiology is a common reason patients seek medical attention. While there are many reasons patients develop diarrhea, microbial insult has been targeted as a major contributor to this disease. Parasites, bacteria, and viruses are part of the spectrum of implicated organisms. Since testing for a specified organism is often inconclusive, costly, and untimely, clinicians often prescribe a trial of empiric antibiotics. Nitazoxanide (NTZ) is a first in class thiazolide antibiotic with activity against anaerobic bacteria, protozoans, helminthes, and gastrointestinal viruses. Furthermore, NTZ has a placebo-like safety profile, high gastrointestinal (GI) concentration, and limited to no activity against probiotic species. The purpose of this review is to evaluate the effectiveness of NTZ as empiric therapy for the treatment of diarrhea of unknown etiology. Methods: A chart review was performed on patients treated with NTZ from April 2006 to April 2007 with complaints of generalized diarrhea not attributed to suspected small intestinal bacterial overgrowth (SIBO), or Clostridium difficile-associated diarrhea (CDAD). Efficacy was measured as patient reported resolution of diarrhea or satisfactory improvement of symptoms by the end of therapy. Patients not returning to the clinic were contacted by telephone to determine resolution of symptoms. Twelve patients met the inclusion criteria for review. Results: Of the 12 patients treated with NTZ, 9 were available for follow-up evaluation. Diarrhea was considered chronic or persistent in 8 of the 9 patients, one patient presented with acute diarrhea. The range of NTZ doses used was 500 mg BID-TID for 3–10 days, the mean dosing regimen was 1166 mg/day for 7.1 days. Overall 8/9 (89%) patients reported resolution of diarrhea or satisfactory improvement. Of note, the one patient failure had been prescribed NTZ 500 mg BID for 7 days, but the patient's insurance company would only allow the patient to receive 3 days of therapy (6 tablets). No clinically significant adverse reactions attributable to NTZ were identified during the study. Conclusion: Nitazoxanide appears to be a safe and effective therapy for the empiric treatment of diarrhea of unknown etiology. Larger controlled clinical trials are warranted to support these findings.