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. 1975 Apr;7(4):462–465. doi: 10.1128/aac.7.4.462

Rapid, Simple Bioassay for 5-Fluorocytosine in the Presence of Amphotericin B

Robert L Kaspar 1, David J Drutz 1
PMCID: PMC429163  PMID: 1096801

Abstract

It is important that serum levels of 5-fluorocytosine (5FC) be measured to insure therapeutic levels while avoiding toxicity. This is particularly true in patients with renal insufficiency. The concurrent use of amphotericin B and 5FC complicates the measurement of 5FC in the serum, since fungi used in conventional bioassay systems are uniformly susceptible to amphotericin B. This paper describes the development of a simple, reliable, 6-h bioassay for 5FC in the presence of amphotericin B. The assay is based upon the fact that 5FC diffuses readily through yeast nitrogen base agar, whereas amphotericin B apparently does not. This assay allows rapid adjustments in therapy of patients receiving both 5FC and amphotericin B and has permitted us to maintain 5FC serum levels between limits of 25 and 120 μg/ml in patients with altered renal function.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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