Renal elimination of ceftazidime during pregnancy

OBJECTIVE: Our purpose was to study the pharmacokinetics of ceftazidime at different stages of pregnancy and in the nonpregnant state to determine whether glomerular filtration rate is altered and whether tubular secretions occurs. STUDY DESIGN: Twelve pregnant women with asymptomatic bacteruria were given a bolus dose of 400 mg of ceftazidime followed by a constant infusion for 4 hours. Inulin was infused simultaneously to determine glomerular filtration rate. Blood samples were drawn every 30 minutes. Urine was collected immediately after the bolus dose and then every hour. The same study procedure was then repeated twice: 2 weeks before the expected delivery and after termination of breast-feeding. RESULTS: At term clearance values were raised by 50% to 100% compared with the values found in the postpartum period. At all observation points a close correlation between inulin and ceftazidime clearance values were found. CONCLUSION: The results strongly indicate that ceftazidime is excreted exclusively by glomerular filtration with no tubular reabsorbtion. During pregnancy the excretion pattern is unaltered, but renal elimination is increased.