Tolvaptan (Jinarc®)

What is tolvaptan and what does it do?

Tolvaptan is used to treat autosomal dominant polycystic kidney disease (ADPKD), an inherited disease that causes small fluid-filled sacs (cysts) to develop in the kidneys, which cause kidney function problems.

Tolvaptan is given to slow down the growth of cysts in the kidney, and therefore help to preserve kidney function for longer. It does this by blocking the effect of vasopressin, a hormone naturally present in the body, which is involved in cyst development.

How do I take my tolvaptan?

Tolvaptan is a tablet which should be swallowed whole and needs to be taken every day in two separate doses, with or without food. Take the larger dose in the morning, and the smaller dose eight hours later.

e.g. For a starting total dose of 60mg daily, take the 45mg tablet in the morning and the 15mg tablet eight hours later.

How will I receive my tolvaptan prescription?

You may be able to collect your initial prescription of tolvaptan from the outpatient pharmacy; however you should only start taking it following confirmation from your clinician that it is safe to do so, based on your blood tests (liver function).

Further prescriptions of tolvaptan will be delivered directly to your home address via the outpatient pharmacy in agreement with the pharmacy at Addenbrooke’s Hospital. If you have any questions about your delivery, please call the numbers on your contact card.

We cannot prescribe the next lot of tolvaptan until we have seen the results of blood and urine tests (see section below “Do I need to have any tests…” )

Are there any side-effects of tolvaptan?

Tolvaptan will make you pass much more urine than before, and will make you more thirsty than usual. Because of the risk of dehydration, you should drink plenty of water or watery drinks (but not grapefruit juice) even if you do not feel thirsty – at least five litres / day. You should also drink water or watery drinks before bed and if you need to get up during the night to pass urine, drink a glass of water then too.

Rarely, tolvaptan can cause injury to your liver, hence the need for frequent blood tests.

Inform your doctor if you experience:

• tiredness
• abdominal pain
• loss of appetite
• dark urine, itching
• yellowing of the skin or eyes (jaundice)
• severe dehydration
• nausea
• vomiting
• joint or muscle pain

If you develop vomiting or diarrhoea for any reason, or a fever, you should ensure you drink plenty of extra fluids to prevent further dehydration. You may need temporarily to stop taking the tolvaptan until things settle down.

Tolvaptan can cause problems with pressure in the eyes and it is important to have annual eye examinations by a qualified optician, particularly if you have a history of glaucoma in your family. You will be asked to let the RGTD clinic know the results

A ‘patient alert card’ is provided by the manufacturer to be given to all patients started on tolvaptan. Please keep this card with you at all times.

Do I need to have any tests or be monitored because I take tolvaptan?

Yes. Although the risk of liver damage is very small, blood and urine tests are required for ongoing treatment - every 4 weeks for the first 18 months and then every 12 weeks. Bloods can be taken at Addenbrooke’s (by appointment), at the Newmarket Road Park and Ride, at your GP surgery or local hospital if you live outside Cambridge. The renal genetics specialist nurse will organise the request forms and liaise with you via MyChart.

We will check the concentration of your blood and urine each time as well.

Where possible we will coordinate these with clinic appointments.

Please make sure you have your blood tests done in the third week of every four week cycle (tolvaptan comes in 28-day packs).

Special warnings and precautions when taking tolvaptan

• Tolvaptan should be avoided if you have previously had an allergic reaction to it or any of the ingredients in the information leaflet in the tablet box.
• If you are unable to pass urine you should not take tolvaptan. Contact your doctor if this occurs whilst taking tolvaptan.
• If you are considering becoming pregnant or become pregnant whilst on tolvaptan, stop taking it and speak to your clinic team as soon as possible.
• You should not breastfeed whilst taking tolvaptan or for four weeks after stopping.

Are there any problems taking tolvaptan with other medicines?

Tolvaptan may interact with some other medicines. Only take tablets prescribed for you by your doctor and check with your doctor or pharmacist before taking any new medicines. Tell your kidney doctor about all the medicines you take.

Whilst taking tolvaptan you should avoid drinking grapefruit juice as this may adversely affect you.

Who can I contact to discuss tolvaptan?

We have provided the following details to help you with managing the blood tests and side effects associated with taking tolvaptan:

Please use MyChart if possible, and ask to be signed up if you are not already on it.

Email dialysis secretary

Telephone Numbers:

Consultant’s secretary: 01223 217828

Nurse Specialist: 01223 217828

Pharmacy: 01223 210301

Further information:

Further information about your tablet can be found in the patient information leaflet found in the tablet / capsule box or on the container.

If you have any other questions about your medication, please contact the medicines helpline on 01223 217502.