Pharmacokinetics of clindamycin phosphate in the first year of life.

The pharmacokinetics of intravenously administered clindamycin phosphate was studied in 40 children less than 1 year of age. Mean peak serum concentrations were 10.92 micrograms/ml in premature infants less than 4 weeks of age, 10.45 micrograms/ml in term infants greater than 4 weeks, and 12.69 micrograms/ml in term infants less than 4 weeks of age. Mean trough concentrations were 5.52, 2.8, and 3.03 micrograms/ml, respectively, in the same groups. Serum half-life was significantly longer (8.68 vs 3.60 hours) in premature compared with term infants less than 4 weeks of age. Both premature and term infants less than 4 weeks had significantly decreased clearance when compared with infants greater than 4 weeks (0.294 and 0.678, respectively, vs 1.58 L/hr). Clearance was significantly greater (1.919 vs 0.310 L/hr) and serum half-life less (1.75 vs 7.57 hours) in infants with body weight greater than 3.5 kg. On the basis of these data it is recommended that in infants greater than 4 weeks or greater than 3.5 kg, intravenous clindamycin dosage be 20 mg/kg/day in four divided doses. In premature neonates less than 4 weeks, the dose should be reduced to 15 mg/kg/day in three divided doses. Term infants greater than 1 week of age may also receive 20 mg/kg/day in four doses.