C max is 4 to 8 mcg/mL (IV). T max is 1 h (IM). Oral absorption is poor.
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.
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.
Renal Function Impairment
End-stage renal disease: t ½ is 24 to 60 h.
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.