Flucytosine (5-FC) Levels: 15-years Experience from the United Kingdom.

A. C. PASQUALOTTO1,2, S. HOWARD 3, C. B. MOORE 3, D. W. DENNING 1,2;

Author address: 

1The Univ. of Manchester, Manchester, United Kingdom, 2Wythenshawe Hosp., Manchester, United Kingdom, 3Regional Mycology Lab., Wythenshawe Hosp., Manchester, United Kingdom.

Abstract: 

Background: 5-FC is an antifungal drug useful in the treatment of cryptococcal meningitis and some Candida and Aspergillus infections. The main limitation of 5-FC is its toxicity, mainly involving the bone marrow or GI tract. Based on its narrow therapeutic index, blood monitoring is recommended. Methods: We reviewed all 5-FC levels performed in a reference center from October 1991 to May 2006. Flucytosine levels (mg/l) were measured by bioassay. Patients were classified as neonates (0-3 months) or non-neonates (all others). Post-dose samples were taken 30 mins after IV infusion or 2 h after oral therapy. The neonate target range for levels were: pre-dose 20-40 and post-dose 50-80 and for non-neonates were: pre-dose 30-40 and post-dose 70-80. Levels > 100 were reported as potentially toxic (PT). Results: 1,360 levels were evaluated in 303 patients, including 64 neonates. Mean number of tests per patient was 4.5 (range, 1-50). For 15.5% of patients levels were random and excluded from analysis. 53.1% were pre-dose and 46.9% post-dose levels. Overall, only 18.1% of levels were in the expected therapeutic range. Low levels were observed in 44.8% of patients, including 6.8% with undetectable levels (
2006

abstract No: 

M-1305

Full conference title: 

46th Interscience Conference on Antimicrobial Agents and Chemotherapy
    • ICAAC 46th