pheral neuropathy, pyrexia, vertigo, sedation, convulsions. psychiatric: confusion, hallucinations, psychosis. miscellaneous: fatigue, hypoglycemia, hypokalemia, weakness, allergic reactions, lyell’s syndrome. to report suspected adverse reactions , contact sigmapharm laboratories, llc, pharmacovigilance at 1-855-332-0731 or fda at 1-800-fda-1088 or www.fda.gov/medwatch.

uring pregnancy only if the potential benefit justifies the potential risk to the fetus. nursing mothers it is not known whether this drug is excreted in human milk. because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from flucytosine capsules, usp, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother. pediatric use the efficacy and safety of flucytosine capsules, usp have not been systematically studied in pediatric patients. a small number of neonates have been treated with 25 to 200 mg/kg/day of flucytosine, with and without the addition of amphotericin b, for systemic candidiasis. no unexpected adverse reactions were reported in these patients. it should be noted, however, that hypokalemia and acidemia were reported in one patient who received flucytosine in combination with amphotericin b, and anemia was observed in a second patient who received flucytosine alone. transient thrombocytopenia was noted in two additional patients, one of whom also received amphotericin b.

e total radioactivity after oral administration was recovered in the urine as intact drug. flucytosine is deaminated (probably by gut bacteria) to 5-fluorouracil. the area under the curve (auc) ratio of 5-fluorouracil to flucytosine is 4%. approximately 1% of the dose is present in the urine as the α-fluoro-β-ureido-propionic acid metabolite. a small portion of the dose is excreted in the feces. the half-life of flucytosine is prolonged in patients with renal insufficiency; the average half-life in nephrectomized or anuric patients was 85 hours (range: 29.9 to 250 hours). a linear correlation was found between the elimination rate constant of flucytosine and creatinine clearance. in vitro studies have shown that 2.9% to 4% of flucytosine is protein-bound over the range of therapeutic concentrations found in the blood. flucytosine readily penetrates the blood-brain barrier, achieving clinically significant concentrations in cerebrospinal fluid. pharmacokinetics in pediatric patients limited data are available regarding the pharmacokinetics of flucytosine capsules, usp administered to neonatal patients being treated for systemic candidiasis. after five days of continuous therapy, median peak levels in infants were 19.6 mcg/ml, 27.7 mcg/ml, and 83.9 mcg/ml at doses of 25 mg/kg (n=3), 50 mg/kg (n=4), and 100 mg/kg (n=3), respectively. mean time to peak serum levels was of 2.5 ± 1.3 hours, similar to that observed in adult patients. a good deal of interindividual variability was noted, which did not correlate with gestational age. some patients had serum levels > 100 mcg/ml, suggesting a need for drug level monitoring during therapy. in another study, serum concentrations were determined during flucytosine therapy in two patients (total assays performed =10). median serum flucytosine concentrations at steady state were calculated to be 57 ± 10 mcg/ml (doses of 50 to 125 mg/kg/day, normalized to 25 mg/kg per dose for comparison). in three infants receiving flucytosine 25 mg/kg/day (four divided doses), a median flucytosine half-life of 7.4 hours was observed, approximately double that seen in adult patients. the concentration of flucytosine in the cerebrospinal fluid of one infant was 43 mcg/ml 3 hours after a 25 mg oral dose, and ranged from 20 to 67 mg/l in another neonate receiving oral doses of 120 to 150 mg/kg/day.