title: Dual Impact of Tolvaptan on Intracellular and Extracellular Water in Chronic Kidney Disease Patients with Fluid Retention.
abstract: Objective Tolvaptan, an oral selective V2-receptor antagonist, is a water diuretic that ameliorates fluid retention with a lower risk of a worsening renal function than conventional loop diuretics. Although loop diuretics predominantly decrease extracellular water (ECW) compared with intracellular water (ICW), the effect of tolvaptan on fluid distribution remains unclear. We therefore examined how tolvaptan changes ICW and ECW in accordance with the renal function. Methods Six advanced chronic kidney disease patients (stage 4 or 5) with fluid retention were enrolled in this study. Tolvaptan (7.5 mg/day) added to conventional diuretic treatment was administered to remove fluid retention. The fluid volume was measured using a bioimpedance analysis device before (day 0) and after (day 5 or 6) tolvaptan treatment. Results Body weight decreased by 2.6%±1.3% (64.4±6.5 vs. 62.8±6.3 kg, p=0.06), and urine volume increased by 54.8%±23.9% (1,215±169 vs. 1,709±137 mL/day, p=0.03) between before and after tolvaptan treatment. Tolvaptan significantly decreased ICW (6.5%±1.5%, p=0.01) and ECW (7.5%±1.4%, p=0.02), which had similar reduction rates (p=0.32). The estimated glomerular filtration rate remained unchanged during the treatment (14.6±2.8 vs. 14.9±2.7 mL/min/1.732m, p=0.35). Conclusion Tolvaptan ameliorates body fluid retention, and induces an equivalent reduction rate of ICW and ECW without a worsening renal function. Tolvaptan is a novel water diuretic that has a different effect on fluid distribution compared with conventional loop diuretics.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Jichi Medical University, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Masuda
authors.forename: Takuya
authors.initials: T
authors.lastname: Murakami
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Igarashi
authors.forename: Kyochika
authors.initials: K
authors.lastname: Okabe
authors.forename: Takahisa
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Shin-Ichi
authors.initials: SI
authors.lastname: Takeda
authors.forename: Takako
authors.initials: T
authors.lastname: Saito
authors.forename: Chuji
authors.initials: C
authors.lastname: Sekiguchi
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Miyazawa
authors.forename: Tetsu
authors.initials: T
authors.lastname: Akimoto
authors.forename: Osamu
authors.initials: O
authors.lastname: Saito
authors.forename: Shigeaki
authors.initials: S
authors.lastname: Muto
authors.forename: Daisuke
authors.initials: D
authors.lastname: Nagata
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D065092:Antidiuretic Hormone Receptor Antagonists / Q000494:pharmacology / Q000627:therapeutic use*; D001552:Benzazepines / Q000494:pharmacology / Q000627:therapeutic use*; D001835:Body Weight / Q000187:drug effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D051436:Renal Insufficiency, Chronic / Q000188:drug therapy*; D000077602:Tolvaptan; D014554:Urination / Q000187:drug effects; D014867:Water
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D001552:Benzazepines; D014867:Water; D000077602:Tolvaptan