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Flucytosine

    Brands

    DEA Class; Rx

    Common Brand Names; Ancobon, 5-FC, 5-fluorocytosine

    • Antifungals, Systemic; 

    Fluorinated pyrimidine antifungal agent; structurally similar to fluorouracil and floxuridine; used mainly in combination with amphotericin B for cryptococcal meningitis; use has decreased due to availability of new antifungals.

    Indicated for treatment of Candidiasis/Cryptococcus Infection

    Other Indications & Uses

    Off-label: chromomycosis

    Hypersensitivity

    Patients with known complete dihydropyrimidine dehydrogenase (DPD) enzyme deficiency

    • Confusion
    • Headache
    • Hallucinations
    • Dizziness
    • Drowsiness
    • Psychosis
    • Parkinsonism
    • Ataxia
    • Sedation
    • Rash
    • Photosensitivity
    • Pruritus
    • Urticaria
    • Temporary growth failure
    • Hypoglycemia
    • Hypokalemia
    • Nausea
    • Vomiting
    • Diarrhea
    • Abdominal pain
    • Loss of appetite
    • Bone marrow suppression
    • Anemia
    • Leukopenia
    • Thrombocytopenia
    • Elevated liver enzymes
    • Hepatitis
    • Azotemia
    • Peripheral neuropathy
    • Paresthesia
    • Weakness

    Measurement of serum creatinine levels should be determined by Jaffé reaction since this drug does not interfere with determination of creatinine values by this method; most automated equipment for measurement of creatinine makes use of the Jaffé reaction

    Electrolytes (because of hypokalemia), hematologic, and renal status of the patient should be determined before therapy instituted; close monitoring of patient during therapy is essential.

    Use extreme caution in patients with impaired renal function; monitor blood concentrations and kidney function in renal impairment; drug can progressively accumulate; dosage adjustments should be made in patients with renal insufficiency to prevent progressive accumulation of active drug

    Not known whether this drug is excreted in human milk; because many drugs are excreted in human milk and because of potential for serious adverse reactions in nursing infants, 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

    Adults

    150 mg/kg/day PO.

    Geriatric

    150 mg/kg/day PO.

    Adolescents

    Safety and efficacy have not been established; however, doses of 150 mg/kg/day PO have been used off-label.

    Children

    Safety and efficacy have not been established; however, doses of 150 mg/kg/day PO have been used off-label.

    Infants

    Safety and efficacy have not been established; however, doses of 150 mg/kg/day PO have been used off-label.

    Neonates

    Safety and efficacy have not been established. Doses up to 150 mg/kg/day PO are the most commonly reported maximum doses; however, up to 200 mg/kg/day PO has been used.

    Flucytosine

    capsule

    • 250mg
    • 500mg