Foscarnet clinical pharmacology
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Clinical Pharmacology
Pharmacokinetics
The pharmacokinetics of foscarnet has been determined after administration as an intermittent intravenous infusion during induction therapy in AIDS patients with CMV retinitis. Observed plasma foscarnet concentrations in four studies (FOS-01, ACTG-015, FP48PK, FP49PK) are summarized in Table 3:
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Distribution
In vitro studies have shown that 14 – 17% of foscarnet is protein bound at plasma drug concentrations of 1 – 1000 μM.
The foscarnet terminal half-life determined by urinary excretion was 87.5 ± 41.8 hours, possibly due to release of foscarnet from bone. Postmortem data on several patients in European clinical trials provide evidence that foscarnet does accumulate in bone in humans; however, the extent to which this occurs has not been determined. In animal studies (mice), 40% of an intravenous dose of FOSCAVIR was deposited in bone in young animals and 7% was deposited in adult animals.
Special Populations
Adults with Impaired Renal Function: The pharmacokinetic properties of foscarnet have been determined in a small group of adult subjects with normal and impaired renal function, as summarized in Table 4:
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Total systemic clearance (CL) of foscarnet decreased and half-life increased with diminishing renal function (as expressed by creatinine clearance). Based on these observations, it is necessary to modify the dosage of foscarnet in patients with renal impairment (see DOSAGE AND ADMINISTRATION).[1]
References
- ↑ "http://www.accessdata.fda.gov/drugsatfda_docs/label/2012/020068s018lbl.pdf" (PDF). External link in
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Adapted from the FDA Package Insert.