Comparison of high-performance liquid chromatography and enzyme-multiplied immunoassay technique to monitor mycophenolic acid in paediatric renal recipients.

Therapeutic drug monitoring (TDM) of mycophenolate mofetil (MMF) is recommended to guide immunosuppression. High-performance liquid chromatography with ultraviolet (HPLC-UV) or the enzyme-multiplied immunoassay technique (EMIT), used to measure mycophenolic acid (MPA) were compared in an exclusive paediatric renal transplant population. Twenty patients were included as part of the pharmacokinetics study of MMF, and 88 additional samples were drawn for TDM. Agreement between HPLC-UV and EMIT was assessed by the Bland-Altman method. With the two methods, pre-dose concentrations were not normally distributed. After logarithmic transformation, their mean was 0.79 +/- 1.16 microg ml(-1) and their mean difference was 0.34 +/- 0.16 microg ml(-1) [95% confidence interval (95%CI 0.30-0.38 microg ml(-1), with antilogarithmic values of these limits of 1.34-1.46 microg ml(-1)). Area under the curve (AUC)(HPLC) and AUC(EMIT) were normally distributed. Their mean was 52.42 +/- 25.91 mg x h/l and their mean difference was 15.22 +/- 8 mg x h/l (95%CI 11.99-18.45 mg x h/l), the Bland-Altman plot showing a bias proportional to the mean. Our data showed the absence of agreement between the HPLC and EMIT methods, with an average positive bias of 15% with the EMIT. Further studies are required to determine which method is best appropriate for TDM of MMF in children.

Excretion of ketoprofen and nalbuphine in human milk during treatment of maternal pain after delivery.

Analgesics are required to prevent and treat postpartum pain, but breast-feeding may be contraindicated, because data on milk transfer are very limited. The present study was undertaken to quantify the transfer of ketoprofen and nalbuphine in milk. Eighteen patients gave their informed consent to participate and completed the study. Following delivery, they received ketoprofen (100 mg/12 hours) and nalbuphine (0.2 mg/kg/4 hours) as an intravenous bolus over 2 to 3 days for postpartum pain. Milk samples were collected during the 12 hours between the third and fourth ketoprofen administrations. Ketoprofen and nalbuphine concentrations were determined with high-performance liquid chromatography. The mean and maximum ketoprofen milk concentrations were 57+/-37 and 91+/-51 ng/mL, respectively. Assuming a milk volume of 150 mL/kg/day, the mean and maximum doses that a breast-fed neonate would ingest during one day are 8.5+/-5.5 and 13.6+/-7.6 microg/kg/day, respectively, and the relative infant dose is 0.31+/-0.17% of the weight-adjusted maternal daily dose. The mean and maximum nalbuphine milk concentrations were 42+/-26 and 61+/-26 ng/mL, respectively. Assuming a milk volume of 150 mL/kg/day, the mean and maximum doses that a breast-fed neonate would ingest during one day is 7.0+/-3.2 and 9.0+/-3.8 microg/kg/day, and the relative infant dose is 0.59+/-0.27% of the weight-adjusted maternal daily dose. Therefore, breast-feeding is permissible when ketoprofen and/or nalbuphine are administered to the mother to treat postpartum pain.

Pharmacokinetics of ganciclovir in pediatric renal transplant recipients.

Ganciclovir (GCV) is effective in preventing and treating cytomegalovirus (CMV) infection in solid organ transplant recipients. The aims of the present study were to determine the pharmacokinetics of GCV administered intravenously (IV) and orally (p.o.) as pre-emptive anti-CMV therapy in pediatric renal transplant recipients and to monitor trough levels and side-effects during pre-emptive therapy. Eleven pediatric renal transplant recipients (aged 11.0+/-3.9 years) were included. The diagnosis of CMV infection, based on two positive pp-65 CMV blood antigen tests at 1 week apart, was made at 39+/-12 days post renal transplantation. They received IV GCV at a dose of 5.0+/-0.3 mg/kg per 12 h for 15 days, followed by GCV p.o. at a dose of 46.7+/-8.2 mg/kg per 12 h for 3 months. Pharmacokinetics (PK) were studied at steady state and GCV plasma concentrations were measured by high-performance liquid chromatography. After IV GCV administration, PK parameters were: C(0)=0.84+/-0.66 microg/ml; C(max)=11.77+/-2.82 microg/ml; AUC(0-12 h)=42.29+/-17.57 microg/ml per hour; Cl=0.13+/-0.05 l/h per kg. After p.o. GCV administration, PK parameters were: C(0)=1.08+/-0.68 microg/ml; C(max)=2.70+/-1.07 microg/ml; AUC(0-12 h)=18.97+/-9.36 microg/ml per hour; Cl/F=2.97+/-1.42 l/h per kg. Bioavailability (F) was 4.9+/-1.2%. Pre-dose concentrations (C(0)) measured under p.o. GCV (n=51) were 1.29+/-0.80 microg/ml (8 C(0) values were below 0.5 microg/ml). Pp-65 CMV blood antigen tests became negative after 16+/-11 days of treatment. GCV was well tolerated. Because of the limited bioavailability, the recommended high doses of p.o. GCV (50 mg/kg per 12 h) were administered and were associated with trough levels over 0.5 microg/ml. In 1 patient who received an erroneously low dosage p.o., CMV resistance to GCV appeared, requiring foscarnet.