tolvaptan at a glance
Medicine class
Vasopressin V2-receptor antagonist; an aquaretic that increases water excretion.
Licensed role
Slowing progression of rapidly progressing ADPKD in eligible adults with chronic kidney disease.
Key practical effect
Marked thirst and frequent urination, including overnight, are expected.
Important monitoring
Regular liver-function, kidney-function, electrolyte and hydration assessment is required.
What is tolvaptan used for?
The selected UK product is licensed for:
Slowing kidney-cyst development and loss of kidney function in adults who had chronic kidney disease stage 1–4 when treatment began and whose ADPKD shows evidence of rapid progression.
How does tolvaptan work?
Vasopressin normally acts at V2 receptors in the kidney to retain water and contributes to cyst growth in ADPKD. Tolvaptan blocks these receptors, increasing free-water loss in urine and reducing vasopressin-driven cyst development.
tolvaptan preparations and strengths
Tablet
Route: Oral
Strengths: 7.5 mg, 15 mg, 30 mg, 45 mg, 45 mg + 15 mg, 60 mg, 60 mg + 30 mg, 90 mg, 90 mg + 30 mg
How to take tolvaptan
Follow the specialist prescription and product label exactly.
Swallow the tablets without chewing, with a glass of water.
Take the morning administration before the morning meal; the later administration may be taken with or without food.
Do not drink grapefruit juice.
Maintain ready access to water and a toilet. Drink when thirsty and replace water lost through overnight urination.
Treatment should be interrupted under specialist guidance when drinking or access to water is significantly limited.
tolvaptan side effects
Common or expected effects
- Thirst, dry mouth and increased urination, including overnight
- Headache, dizziness, tiredness or weakness
- Diarrhoea or abdominal discomfort
- Dehydration or raised blood sodium
- Raised uric acid or gout
- Abnormal liver blood tests
Get urgent medical advice
- Possible liver injury: jaundice, dark urine, itching, loss of appetite, persistent nausea, marked tiredness or upper abdominal pain
- Serious allergic reaction: facial or tongue swelling, widespread rash, wheezing or breathlessness
- Severe dehydration, confusion, fainting, seizures or inability to pass urine
tolvaptan in pregnancy
Tolvaptan is contraindicated during pregnancy because human information is limited and animal studies found reproductive toxicity. Reliable contraception is required during treatment; anyone planning pregnancy or who may be pregnant should contact the specialist team promptly.
tolvaptan while breastfeeding
Tolvaptan is contraindicated while breastfeeding. It is unknown whether it enters human milk, and a risk to the infant cannot be excluded; discuss alternatives with the specialist prescriber.
tolvaptan interactions
Check all prescribed, non-prescribed and herbal products with the specialist pharmacist or prescriber. Important examples include:
Strong or moderate CYP3A inhibitors, including clarithromycin, itraconazole, ritonavir, fluconazole, erythromycin, diltiazem and verapamil
They can substantially increase tolvaptan exposure and may require specialist adjustment or an alternative.
Grapefruit juice
It increases tolvaptan exposure and must be avoided.
Potent CYP3A inducers, including rifampicin, carbamazepine, phenytoin and St John’s wort
They can reduce tolvaptan exposure and effectiveness and should be avoided.
Common questions about tolvaptan
Answers are fully visible for fast scanning and source review.
Why does tolvaptan make me so thirsty?
It blocks vasopressin in the kidneys, causing more water to leave the body as urine. Thirst is an expected effect, but severe thirst with dizziness, fainting or confusion needs prompt assessment.
Does tolvaptan cure ADPKD?
No. It is intended to slow cyst growth and loss of kidney function in eligible people; it does not remove existing cysts or eliminate ADPKD.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.