Formulary
Flucytosine: Indications, Dosing, Side Effects and Interactions
Flucytosine clinical drug profile including indications, dosing, side effects, cautions and interactions.
MedNext Academy | 3 min read
Flucytosine: Indications, Dosing, Side Effects and Interactions
Flucytosine clinical drug profile including indications, dosing, side effects, cautions and interactions.
Indications and dose
**Systemic yeast and fungal infections,Adjunct to amphotericin B in severe systemic candidiasis and in other severe or long-standing infections**
- **Adult** (By Intravenous Infusion): Usual dose 200 mg/kg daily in 4 divided doses usually for not more than 7 days, alternatively 100-150 mg/kg daily in 4 divided doses, lower dose may be sufficient for extremely sensitive organisms.
**Cryptococcal meningitis (adjunct to amphotericin B)**
- **Adult** (By Intravenous Infusion): 100 mg/kg daily in 4 divided doses for 2 weeks.
**Systemic yeast and fungal infections, Adjunct to amphotericin B in severe systemic candidiasis and in other severe or long-standing infections for flucytosine**
- **Neonate** (By intravenous infusion, or by mouth): 50 mg/kg every 12 hours.
- **Child** (By intravenous infusion, or by mouth): Usual dose 50 mg/kg every 6 hours usually for not more than 7 days, alternatively 25-37.5 mg/kg every 6 hours usually for not more than 7 days, lower dose may be sufficient for sensitive organisms.
**Cryptococcal meningitis (adjunct to amphotericin B) for flucytosine**
- **Neonate** (By intravenous infusion, or by mouth): 50 mg/kg every 12 hours.
- **Child** (By intravenous infusion, or by mouth): 25 mg/kg every 6 hours for 2 weeks.
Cautions
Blood disorders; elderly; partial dihydropyrimidine dehydrogenase deficiency
Contraindications
Complete dihydropyrimidine dehydrogenase deficiency
Side effects
Frequency not known Agranulocytosis; aplastic anaemia; blood disorder; cardiotoxicity; confusion; diarrhoea; hallucination; headache; hepatic disorders; leucopenia; nausea; rash; sedation; seizure; thrombocytopenia; toxic epidermal necrolysis; ventricular dysfunction; vertigo; vomiting
Interactions
**Other interactions (4):**
- This includes anti-infective agents (such as dapsone, pentamidine, flucytosine, amphotericin B, trimethoprim/sulfamethoxazole), immunosuppressants (e.g.
- This includes nucleoside (e.g.
- Concomitant treatment, especially acute therapy, with potentially nephrotoxic or myelosuppressive drugs (eg.
- Antifungals Whilst synergy between amphotericin and flucytosine has been reported, concurrent use may increase the toxicity of flucytosine by possibly increasing its cellular uptake and/or impairing...
Pregnancy
Teratogenic in animal studies; manufacturer advises use only if potential benefit outweighs risk.
Breast feeding
Manufacturer advises avoid.
Renal impairment
Dose adjustments Use 50 mg/kg every 12 hours if creatinine clearance 20-40 mL/minute; use 50 mg/kg every 24 hours if creatinine clearance 10-20 mL/minute; use initial dose of 50 mg/kg if creatinine clearance less than 10 mL/minute and then adjust dose according to plasma-flucytosine concentration. Monitoring In renal impairment liver- and kidney-function tests and blood counts required weekly.
Medicinal forms
Medicinal forms No licensed medicines listed.
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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