Question 1

What is Flucytosine used for?

Accepted Answer

Flucytosine is indicated for: Cryptococcosis (with amphotericin B).

Question 2

What routes can Flucytosine be administered by?

Accepted Answer

Available routes: PO.

Question 3

Which species have cited Flucytosine dosing data?

Accepted Answer

Flucytosine dosing in the ExoticRx formulary covers 2 species: Cat (Domestic), Dog (Domestic).

Question 4

Is Flucytosine a controlled substance?

Accepted Answer

Flucytosine is not federally scheduled as a controlled substance, but is veterinary prescription only in most jurisdictions.

Question 5

What are the warnings or contraindications for Flucytosine?

Accepted Answer

Rapid resistance if used alone — always combine with amphotericin B or azole. Bone marrow suppression, GI toxicity. Monitor CBC. Teratogenic.

Question 6

What are the side effects of Flucytosine?

Accepted Answer

Rapid resistance if used alone — always combine with amphotericin B or azole. Bone marrow suppression, GI toxicity. Monitor CBC. Teratogenic.

Question 7

How does Flucytosine work?

Accepted Answer

Converted to 5-fluorouracil inside fungal cells, inhibiting DNA and RNA synthesis. Synergistic with amphotericin B.

Species	Route	Dose	Frequency	Evidence	Source
Dog (Domestic)	PO	25–50 mg/kg	q6-8h	Moderate	Plumb's Veterinary Drug Handbook, 9th Ed
Cat (Domestic)	PO	25–50 mg/kg	q6-8h	Moderate	Plumb's Veterinary Drug Handbook, 9th Ed

Flucytosine

Drug Class