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Treating Candida glabrata with Boric Acid and Flucytosine
Abstract & Commentary
Synopsis: In cases of azole-refractory vaginitis caused by Candida glabrata, topical boric acid and flucytosine are useful therapies.
Source: Sobel JD, et al. Am J Obstet Gynecol. 2003; 189:1297-1300.
This retrospective review summarizes the clinical outcome and safety among 141 patients who were treated with boric acid and flucytosine for culture-proven Candida glabrata. These data were collected at both Wayne State University School of Medicine and Ben Gurion University. Symptoms seen in these patients were similar to symptoms related to other species. The median pH was 4.4; and on budding yeast was seen in 81% of saline wet-mount preparations. Forty-seven of 73 cases of symptomatic vaginitis (64%) became culture negative and had improved symptoms after daily treatment with boric acid suppositories, 600 mg. Another 23 patients (32%) remained culture positive while 3 were lost to follow-up. Thirty patients were offered intravaginal flucytosine, 26 of whom had previously been treated with boric acid and had either short-term treatment failure or a relapse. Of these, 27 were treated successfully, 2 failed therapy, and 1 was lost to follow-up.
Comment by Frank W. Ling, MD
I admit it. You might find this study of limited value. Why? For one, maybe you choose not to buy into data generated from retrospective chart reviews, because you want to use only evidence-based medicine to treat your patients. Alternatively, maybe you just don’t see many patients whose yeast symptoms do not respond to azole therapy. Nevertheless, there are things to be learned from this article. Read on.
Sobel and colleagues have been reporting on C glabrata for a decade. Unfortunately the true prevalence of this non-albicans species is unknown, and the treatment outcomes remain sketchy at best. This particular study doesn’t add much science, but it does add more cases. Insufficient numbers of patients with documented C glabrata have made a randomized trial to investigate treatment impossible.
We do glean a couple of useful pearls here. First, 600 mg boric acid gelatin capsules are effective in patients whose yeast infections fail azole therapy, with 3 weeks of therapy being no better than 2 weeks. We also discover that flucytosine 5 mg intravaginally every night for 14 days is effective when boric acid is not. The technique of formulating the vaginal cream includes: 14 500 mg capsules of flucytosine reduced to a fine powder and mixed with glycerin to form a smooth paste. This mixture is then mixed with a hydrophilic ointment base or cold cream to 45 gm. The result is two 2-oz tubes that will last for 14 days.
So how often will you need it? Ever? At least these 2 options can be tucked away for that resistant case that doesn’t respond in spite of multiple treatment courses of more mainstream options. With the greater use of vaginal cultures to identify other species of Candida, both boric acid and flucytosine cream may be just what the doctor ordered for select patients.