| Absorption and Distribution: |
| Flucytosine is rapidly and well absorbed from the GI tract with plasma levels peaking in 1-2 hr in animals that have received the drug for several days. The drug is widely distributed in the body with a volume of distribution approximating the total body water. Flucytosine is minimally bound to plasma proteins. There is excellent penetration into body fluids such as the CSF, synovial fluids, and aqueous humor. |
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| Biotransformation and Excretion: |
| Nearly all of an oral dose (85-95%) is excreted unchanged. Flucytosine is principally excreted by glomerular filtration (>80%). The clearance of flucytosine is approximately equivalent to that of creatinine. In renal failure, elimination of flucytosine is markedly impaired. |
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| Pharmacokinetics: |
| With normal renal function, the plasma half-life of flucytosine is usually 2-4 hr but may be up to 200 hr with oliguria. Serum levels of 50-100 µg/mL are usually in the therapeutic range. |
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