Tolvaptan
Tolvaptan increases excretion of water by blocking vasopressin V2 receptors. Its use and monitoring differ substantially between low-sodium states and autosomal dominant polycystic kidney disease.
Key points
- Tolvaptan can change fluid balance and blood sodium quickly, so thirst, access to water and laboratory monitoring are important.
- Treatment for polycystic kidney disease requires particular attention to liver injury risk and ongoing liver tests.
- Products and treatment protocols used for different indications are not automatically interchangeable.
Select a listed product and pack to order online. Whether it suits you depends on specialist assessment of the indication; ask your doctor or pharmacist.
What tolvaptan is used for
Tolvaptan may be used in selected cases of hyponatraemia or autosomal dominant polycystic kidney disease. The treatment setting, goals and monitoring are different for each use.
How it works
Blocking vasopressin V2 receptors reduces water reabsorption in the kidneys. This can raise blood sodium in selected patients and can affect cyst-related pathways in polycystic kidney disease.
Important safety checks
The clinical team should review liver and kidney function, sodium concentration, dehydration risk, ability to sense thirst and access water, and interacting medicines. Strong enzyme inhibitors can substantially change tolvaptan exposure.
When to seek urgent care
Seek urgent help for confusion, severe weakness, fainting, inability to drink, very little urine, repeated vomiting, yellow skin or eyes, dark urine, severe upper-abdominal pain or a serious allergic reaction.
Further reading
What is tolvaptan used for?
Tolvaptan is used for some cases of low blood sodium (hyponatraemia) and for autosomal dominant polycystic kidney disease. The treatment goals and monitoring differ for each use.
How does tolvaptan work?
Tolvaptan blocks vasopressin V2 receptors in the kidneys, so the kidneys hold on to less water and you pass more urine.
Which tolvaptan product can I order on SGMeds?
The tolvaptan product on SGMeds is Samsca, and its page gives the strengths and pack sizes.
How long does tolvaptan take to work?
Tolvaptan starts working in about 2 to 4 hours.
What are the side effects of tolvaptan?
Common side effects include thirst, passing a lot of urine, dry mouth and nausea. Serious side effects are severe liver injury and nerve damage from correcting sodium too fast (osmotic demyelination syndrome), which need urgent medical attention.
Who should not take tolvaptan?
Do not take it if you are allergic to tolvaptan, cannot pass urine (anuria), or have low blood volume with low sodium (hypovolaemic hyponatraemia).
How is tolvaptan priced?
The product on this page shows a price for each strength and pack size in Singapore dollars, converted from US dollars, so the exchange rate can change the final amount. Larger packs usually cost less per tablet.
Payment and prices →Can I order tolvaptan without a prescription?
Yes. SGMeds does not ask for a prescription to order tolvaptan: we place the order with our pharmacy partner, which prepares it and arranges delivery on your behalf.
Ordering without a prescription →Do you deliver tolvaptan to Singapore?
Yes. Parcels go to Singapore and Malaysia by Express shipping (tracked, up to 1 week) or Regular shipping (up to 3 weeks).
How ordering works →