Drug Interaction Report

MONITOR: Drugs that impair glomerular filtration may prolong the half-life of flucytosine and lead to accumulation. Prolonged flucytosine serum concentrations of greater than 100 mcg/mL may increase the risk of gastrointestinal, hepatic, and hematologic toxicity.

MANAGEMENT: Caution is advised if flucytosine is used in patients who have recently received or are receiving treatment with potentially nephrotoxic drugs (e.g., aminoglycosides; polypeptide, glycopeptide, and polymyxin antibiotics; amphotericin B; adefovir; cidofovir; tenofovir; foscarnet; cisplatin; deferasirox; gallium nitrate; lithium; mesalamine; certain immunosuppressants; intravenous bisphosphonates; intravenous pentamidine; high intravenous dosages of methotrexate; high dosages and/or chronic use of nonsteroidal anti-inflammatory agents). Renal function and flucytosine blood levels should be closely monitored during therapy, and the dose or dosing interval should be adjusted to maintain flucytosine concentrations below 100 mcg/mL.