Tolvaptan Dosing and Management in ADPKD

Initial Dosing and Titration

The KDIGO guidelines recommend starting tolvaptan at 45 mg upon waking and 15 mg eight hours later, then titrating weekly to a target dose of 90 mg in the morning and 30 mg in the afternoon, continuing treatment until approaching kidney replacement therapy if well-tolerated 1
The initial dosing protocol involves a starting dose of 45 mg upon waking, followed by 15 mg eight hours later, with a titration schedule that increases the dose after at least 1 week if tolerated 1
The target dose is 90 mg in the morning and 30 mg in the afternoon, with a clear three-step titration approach that balances efficacy with tolerability 1

The American College of Nephrology, as reflected in the KDIGO guidelines, recommends continuing tolvaptan until approaching kidney replacement therapy if well-tolerated 1
Treatment can be continued in patients aged >55 years, and when eGFR falls below 25 ml/min/1.73 m² if well-tolerated 1
For pediatric patients, tolvaptan is not routinely recommended, but off-label use can be considered at clinician discretion in children at high risk of early progression based on large total kidney volume, rapid kidney growth, or concerning family history 4

The KDIGO guidelines recommend monthly liver function tests for the first 18 months, and every 3 months thereafter until drug discontinuation, with morning blood samples obtained before the tolvaptan dose 1
Discontinuation criteria for hepatotoxicity include permanently discontinuing if ALT or AST increase to ≥3× upper limit of normal (ULN), and discontinuing if ALT or AST >2× ULN with signs/symptoms of liver injury 1
Serum sodium monitoring is essential to assess adequacy of water intake, with morning samples before tolvaptan dose providing insight into hydration status 1

The KDIGO guidelines emphasize the importance of adequate water intake, with patients required to drink enough water to replace urinary losses, and counsel patients to drink liquids without sugar or fat, and adopt low-sodium intake to reduce polyuria 1
Target water intake is 2-3 liters per day, with low osmolar intake reducing the degree of polyuria and making treatment more tolerable 2
Common pitfalls to avoid include inadequate fluid counseling, missing the sick-day plan, insufficient monitoring, ignoring drug interactions, and premature discontinuation 1, 3