Therapeutic drug monitoring of lopinavir/ritonavir in pediatric patients

CURRAS V1; HOCHT C1; MECIKOVSKY D2, BOLOGNA R2, BRAMUGLIA GF1, RUBIO MC1

Córdoba- Argentina

Congreso; XXXVIII reunión anual de la Asociación Argentina de Farmacología Experimental; 2006

Asociación Argentina de Farmaoclogía Experimental

Therapeutic drug monitoring of lopinavir/ritonavir in pediatric patients Curras V1; Hocht C1; Mecikovsky D2, Bologna R2, Bramuglia GF1, Rubio MC1 1Cátedra de Farmacología, Facultad de Farmacia y Bioquímica, UBA;  2 Servicio de Infectología, Hospital Garrahan. Buenos Aires, Argentina. e mail: verocurras@yahoo.com The aim of this work is to describe the results of therapeutic drug monitoring (TDM) in pediatric HIV – infected patients who are being treated with lopinavir/ ritonavir (LPV/r) containing regimens. Twenty five patients were included in this work. Fifty three lopinavir plasma levels were determined by HPLC. The average LPV dosage used was 19 mg/kg/day. Age range: 8 months to 19 years old. Only 3 of the patients yielded subtherapeutic levels (through < 1 µg/mL), although these reference levels were determined for adult patients. In two of these patients, dosage was increased by 50%, and a new TDM was performed, leading to levels inside the therapeutic range. Mean concentration between 1.5-2.0 h after drug administration was 5.82 ug/ml (SD: 3.42 ug/ml). The mean concentration of a second peak level obtained between 2.5-3.0 hs was 8.7 ug/ml (SD: 2.94 ug/ml). Although in previous works with other protease inhibitors we showed that a high percentage of trough levels were below the therapeutic range (75% for nelfinavir, 55% for indinavir/r). the less variability observed with lopinavir/r could be atributted, in part, to the presence of ritonavir in the same formulation, since it could assure the “booster” effect of ritonavir that is absorbed simultaneously with lopinavir.