About tolvaptan
Vasopressin V2 receptor antagonist
Used for
- Treats low blood sodium in selected patients with euvolemic or hypervolemic hyponatremia.
- Slows kidney cyst growth in adults with rapidly progressing autosomal dominant polycystic kidney disease (ADPKD).
Usual adult dose
Hyponatremia: usually starts at 15 mg once daily, adjusted by a clinician. ADPKD: usually 45 mg on waking and 15 mg eight hours later, increased gradually if tolerated.
Common side effects
- Thirst and increased urination
- Dry mouth
- Fatigue or weakness
- Liver injury, especially with long-term ADPKD treatment
Important warnings
- Starting or restarting treatment for low sodium requires hospital monitoring.
- Can cause dehydration, low blood volume, and overly rapid sodium correction.
- ADPKD treatment requires regular liver blood tests.
- Avoid in people unable to sense or respond to thirst.
Pregnancy
Human pregnancy information is limited; use is generally avoided unless clearly needed.
Breastfeeding
Breastfeeding is not recommended during treatment because effects on the infant are uncertain.
Interactions
- Strong CYP3A inhibitors can greatly increase tolvaptan levels.
- Strong CYP3A inducers can reduce its effectiveness.
- May increase digoxin levels.
- Avoid grapefruit and grapefruit juice.
AI-generated from general medical knowledge, not from this product's official leaflet. It may be incomplete or out of date. Not medical advice — ask a pharmacist or doctor before making any decision.