Short-term Renal Hemodynamic Effects of Tolvaptan in Subjects With Autosomal Dominant Polycystic Kidney Disease (ADPKD)

Renal function was assessed during screening with the estimated glomerular filtration rate (eGFR), which was calculated with the 4-variable modification of diet in renal disease (MDRD) equation using a minimum of 2 creatinine measurements. The eGFR values were used to categorize participants into 1 of 3 mutually exclusive strata (\> 60 \[Group A\], 30 to 60 \[Group B\], and \< 30 \[Group C\] mL/min/1.73 m\^2). Each of the 3 groups received the same tolvaptan treatment. During the 3-week treatment period, participants were up-titrated on a weekly basis from 45/15 mg to 60/30 mg to 90/30 mg (AM and PM \[8 hours later\] split-dose) to the maximally tolerated dose. The 3-week treatment period was followed by a 3-week post-treatment period during which no study medication was administered. The effects of the highest tolerated split-dose of tolvaptan on renal hemodynamics and pharmacokinetic and pharmacodynamic parameters were assessed throughout the 6 weeks of the study. The reversibility of changes during the post-treatment period after withdrawal of the drug was determined and the acute transitory effects on kidney volume were also explored.