Abstract
BACKGROUND: Renally adjusted lamivudine dosages are effective. However, some of the kidney failure patients managed with lamivudine-containing regimens are failing to suppress HIV in peritoneal dialysis (CAPD) effluent. The steady-state lamivudine pharmacokinetics among these patients was evaluated. METHODS: This overnight open-label pharmacokinetic study enrolled participants living with HIV and managed with CAPD. Lamivudine levels in blood serum and CAPD effluent samples were quantified using liquid chromatography coupled with a mass spectrometer. Pharmacokinetic measures were obtained through non-compartmental analysis. RESULTS: Twenty-eight participants were recruited with a median antiretroviral (ARV) drug duration of 8 (IQR,4.5-10.5) years and a CAPD duration of 13.3 (IQR,3.3-31.9) months. 14.3% (4/28) had detectable unsuppressed HIV-1 viral load in CAPD effluents. The majority (78,6%,22/28) of participants received a 50 mg dose, while 10.7% (3/28), and another 10.7% (3/28) received 75 mg and 300 mg dosages, respectively. Among those treated with 75 and 300 mg, 66.7% (2/3) and 33.3% (1/3) had detectable HIV-VL in CAPD, respectively. The peritoneal membrane characteristics and CAPD system strengths were variable across the entire study population. Lamivudine exposure was increased in blood serum (50 mg-AUC(0-24 h), 651.3 ng/mL; 75 mg-AUC(0-24 h), 677.84 ng/mL; 300 mg-AUC(0-24 h), 3135.89 ng/mL) compared to CAPD effluents (50 mg-AUC(0-24 h), 384.91 ng/mL; 75 mg-AUC(0-24 h), 383.24 ng/mL; 300 mg-AUC(0-24 h), 2001.60 ng/mL) among the entire study population. The C(max) (50 mg, 41.5 ng/mL; 75 mg, 53.2 ng/mL; 300 mg, 199.1 ng/mL) and C(min) (50 mg, 17.8 ng/mL; 75 mg, 16.4 ng/mL; 300 mg, 76.4 ng/mL) measured in serum were within the therapeutic levels. CONCLUSIONS: Steady-state lamivudine pharmacokinetic measures were variable among the entire study population. However, the total lamivudine exposure was within the therapeutic levels.