Population Pharmacokinetic Simulations for Dose Optimization of Tenofovir Disoproxil Fumarate in HIV-Infected Patients with Moderate-to-Severe Renal Impairment.

Tenofovir disoproxil fumarate (TDF) requires dosage adjustments from the standard 300 mg once daily to every 48-96 h for moderate-to-severe renal impairment to avoid excessive exposure. However, this extended interval can lead to variable drug exposure and inconvenience. This study aimed to utilize the population pharmacokinetic (PPK) models to optimize TDF dosing regimens for HIV-infected patients with renal impairment. A systematic literature search was conducted across PubMed, Cochrane Library, and Scopus databases to identify relevant PPK studies of TDF in HIV-infected patients. From the included studies, the PPK models and associated parameters were extracted. Monte Carlo simulations (n = 2000) were performed to generate concentration-time profiles and derive PK parameters compared against reference ranges. For moderate renal impairment, the TDF 150 mg once-daily regimen achieved cumulative exposure comparable to the approved 300 mg every-other-day regimen. In severe renal impairment, TDF 75-100 mg administered once daily provided similar cumulative exposure as 300 mg every 72-96 h regimen while maintaining daily exposure comparable to the standard dose in patients with normal renal function. The approved extended dosing intervals of 72-96 h exhibited high drug exposure variability, initially resulting in supratherapeutic levels followed by suboptimal levels preceding the subsequent dose administration. In conclusion, administering smaller once-daily doses of TDF maintains consistent daily drug exposure comparable to the standard dose in patients with normal renal function while reducing variability in drug exposure, potentially mitigating the risk of nephrotoxicity. However, additional clinical studies are required to confirm these findings.