Tolvaptan Guide Tier 1 — Approved
Tolvaptan — the only approved disease-modifying therapy for ADPKD
It slows progression in appropriate patients. It is not a cure. It requires real monitoring. Here is what the evidence actually says.
How tolvaptan works
Blocks vasopressin at kidney collecting ducts → reduces cAMP → cysts grow more slowly.
Tolvaptan is a vasopressin V2 receptor antagonist. Vasopressin (ADH) normally signals kidney cells to conserve water. In ADPKD, this signaling also drives the cyclic AMP (cAMP) pathway that fuels cyst cell growth and fluid secretion.
By blocking the V2 receptor, tolvaptan lowers cAMP in collecting duct cells. The result: cysts accumulate fluid more slowly, kidney volume grows more slowly, and eGFR declines more slowly in patients who qualify.
The tradeoff: because it blocks water resorption, you produce 3–5 litres of urine per day. You will be thirsty. This is the mechanism — not a side effect to push through without fluids.
Brand names and approval status
- Jynarque — US FDA approved (2018) for rapidly progressing ADPKD
- JINARC — EMA approved (EU, 2015)
- Samsca — older brand, used off-label for ADPKD before dedicated approval
In the US, dispensing requires enrollment in the JYNARQUE REMS program due to liver toxicity risk. Your prescribing centre will manage this.