Absorption
C max is 4 to 8 mcg/mL (IV). T max is 1 h (IM). Oral absorption is poor.

Distribution
Vd is 0.2 to 0.4 L/kg. Protein binding is 0% to 10%. The t ½ is 5 to 15 min. Distributed to extracellular ascitic, pericardial, pleural, synovial, lymphatic, and peritoneal fluids; body tissues; high concentrations in urine; low concentrations in breast milk, line spread function, and sputum. Crosses the placenta but does not cross the blood-brain barrier.

Elimination
The t ½ is 2 h. Peritoneal dialysis is 25% removed in 48 to 72 h. Primary route is renal-glomerular filtration; 50% is removed during a 4 to 6 h hemodialysis period.

Special Populations
Renal Function Impairment
End-stage renal disease: t ½ is 24 to 60 h.

Children
In infants younger than 1 wk old and less than 1,500 g, Vd is up to 0.68 L/kg; more than 1,500 g, Vd is up to 0.58 L/kg. The t ½ is 5 to 8 h.

Drugs with nephrotoxic potential (eg, amphotericin, cephalosporins, enflurane, methoxyflurane, vancomycin)
May increase risk of nephrotoxicity.

Loop diuretics
May increase risk of auditory toxicity.

Neuromuscular blocking agents
May enhance effects of these agents.

Polypeptide antibiotics
May increase risk of respiratory paralysis and renal function impairment.