Flucytosine

CLINICAL USE


Antifungal agent

DOSE IN NORMAL RENAL FUNCTION

100–200 mg/kg per day in 4 divided doses

PHARMACOKINETICS

  • Molecular weight &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp :129.1
  • %Protein binding &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp :2–4
  • %Excreted unchanged in urine &nbsp &nbsp : 90
  • Volume of distribution (L/kg) &nbsp &nbsp &nbsp :0.65–0.91
  • half-life – normal/ESRD (hrs)&nbsp &nbsp &nbsp :3–6/75–200

    DOSE IN RENAL IMPAIRMENT

    GFR (mL/MIN)

    20–40 50 mg/kg 12 hourly
  • 10 to 20 &nbsp &nbsp : 50 mg/kg 24 hourly
  • <10 &nbsp &nbsp &nbsp &nbsp &nbsp : 50 mg/kg then dose according to levels. Dose of 0.5–1 g daily is usually adequate

    DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

  • CAPD &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp:Dialysed. Give 50 mg/kg daily in 4 divided doses. Monitor levels

  • HD &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp :Dialysed. Dose as in GFR
  • <10 &nbsp &nbsp &nbsp &nbsp &nbsp : mL/min, given post dialysis. Monitor trough level pre dialysis, and reduce post-dialysis dose accordingly
  • HDF/high flux &nbsp :Dialysed. Dose as in GFR
  • <10 &nbsp &nbsp &nbsp &nbsp &nbsp : mL/min, given post dialysis. Monitor trough level pre dialysis, and reduce post-dialysis dose accordingly
  • CAV/VVHD &nbsp &nbsp &nbsp:Dialysed. Give dose as in GFR 10 to 20 mL/min and monitor blood levels, pre dose

    IMPORTANT DRUG INTERACTIONS

    Potentially hazardous interactions with other drugsCytarabine: concentration of flucytosine possibly reduced

    ADMINISTRATION

    Reconstition

    Route

    IV peripherally through a blood filter

    Rate of Administration

    20–40 minutes

    Comments

    OTHER INFORMATION

    Monitor blood levels 24 hours after therapy commences. Pre-dose level 25–50 mg/L is usually adequate. Do not exceed 80 mg/L250 mL intravenous flucytosine infusion contains 34.5 mmol sodiumBone marrow suppression more common in patients with renal impairmentTablets available on named patient basis onlyCan be given IP at a dose of 50 mg/L