subjects (n=10) following IV administration over 30 minutes of 1000 mg dalbavancin (Day 1) and 500 mg dalbavancin (Day 8).
No apparent accumulation of dalbavancin was observed following multiple IV infusions administered once weekly for up to eight weeks, with 1000 mg on Day 1 followed by up to seven weekly 500 mg doses, in healthy adults with normal renal function.
Distribution: Dalbavancin is reversibly bound to human plasma proteins, primarily to albumin. The plasma protein binding of dalbavancin is approximately 93% and is not altered as a function of drug concentration, renal impairment, or hepatic impairment. The mean concentrations of dalbavancin achieved in skin blister fluid remain above 30 mg/L up to 7 days (approximately 146 hours) post dose, following 1000 mg IV dalbavancin. The mean ratio of the AUC0-144 hrs in skin blister fluid/AUC0-144 hrs in plasma is 0.60 (range 0.44 to 0.64).
Metabolism: In vitro studies using human microsomal enzymes and hepatocytes indicate that dalbavancin is not a substrate, inhibitor, or inducer of CYP450 isoenzymes. A minor metabolite of dalbavancin (hydroxy-dalbavancin) has been observed in the urine of healthy subjects. Quantifiable concentrations of the hydroxy-dalbavancin metabolite have not been observed in human plasma (lower limit of quantitation = 0.4 µg/mL) [see Drug Interactions (7.2)].
Excretion: Following administration of a single 1000 mg dose in healthy subjects, 20% of the dose was excreted in feces through 70 days post dose. An average of 33% of the administered dalbavancin dose was excreted in urine as unchanged dalbavancin and approximately 12% of the administered dose was excreted in urine as the metabolite hydroxy-dalbavancin through 42 days post dose.
Specific Populations
Renal Impairment:The pharmacokinetics of dalbavancin were eva luated in 28 subjects with varying degrees of renal impairment and in 15 matched control subjects with normal renal function. Following a single dose of 500 mg or 1000 mg dalbavancin, the mean plasma clearance (CLT) was reduced 11%, 35%, and 47% in subjects with mild (CLCR 50 to 79 mL/min), moderate (CLCR 30 to 49 mL/min), and severe (CLCR less than 30 mL/min), renal impairment, respectively, compared to subjects with normal renal function. The clinical significance of the decrease in mean plasma CLT, and the associated increase in AUC0-∞ noted in these pharmacokinetic studies of dalbavancin in subjects with severe renal impairment has not been established [see Dosage and Administration (2.2) and Use in Specific Populations (8.6)].
No dosage adjustment is necessary for patients with CLCR greater than 30 mL/min or patients receiving hemodialysis. The recommended two-dose regimen for dalbavancin in patients with severe renal impairment who are not receiving regularly scheduled hemodialysis is 750 mg followed one week later by 375 mg.
Dalbavancin pharmacokinetic parameters in subjects with end-stage renal disease receiving regularly scheduled hemodialysis (three times/week) are similar to those observed in subjects with mild to moderate renal impairment, and less than 6% of an administered dose is removed after three hours of hemodialysis. Therefore, no dosage adjustment is recommended for patients receiving regularly scheduled hemodialysis, and dalbavancin may be administered without regard to the timing of hemodialysis in such patients [see Dosage and Administration (2.1) and Overdosage (10)].
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