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Tolvaptan

Last updated on 15/07/2021.

Overview   |   Dosage   |    Side Effects   |   Precautions   |   Tips   |   Where To Buy  

GENERIC NAME: Tolvaptan

CHINESE NAME: 托伐坦

BRAND NAME(S) IN HONG KONG: Jinarc 佳腎康, Samsca

DRUG CLASS: Endocrine Drugs

SUB CLASS: Vasopressin receptor antagonists 

USED FOR: Autosomal dominant polycystic kidney disease, Chronic hyponatremia with euvolemia or hypervolemia

AVAILABLE DOSAGE FORMS:
– 15 mg, 30 mg, 45 mg + 15 mg, 60 mg + 30mg, 90 mg + 30mg (tablets)

What is Tolvaptan for?

Tolvaptan belongs to the class of endocrine drugs inhibiting vasopressin receptors and their subsequent actions to increase urine output. It is used to treat autosomal dominant polycystic kidney disease and chronic hyponatremia with euvolemia or hypervolemia.

How to use it?

Tolvaptan is administered as tablets in Hong Kong. It differs little regarding what time in a day you take the pills, but it has to be consistent between days. For kidney disease patients, the dose depends on how far it is from the desired urine concentration. For hyponatremic patients, the dose depends on the serum sodium conditions.

Autosomal dominant polycystic kidney disease
Adult and elderly
The initial dose is 45 mg after waking up and 15 mg 8 hours later (45 + 15). Increase dose after at least 7 days based on body response and tolerability to 90 mg daily (60 + 30) and then 120 mg daily (90 + 30).

Chronic hyponatremia with euvolemia or hypervolemia
Adult and elderly
The initial dose is 15 mg once daily. Increase dose after 24 hours based on body response and tolerability to 30 mg daily and then 60 mg daily. Do not use for more than 30 days.

What are the side effects of Tolvaptan?

Common side effects of Tolvaptan include, but not limited to, fatigue, dizziness, increased thirst, dry mouth, nausea, diarrhea and frequent alkaline urination.

Who should not take Tolvaptan?

– People who are allergic to Tolvaptan or any component of the formulation
– People also on strong CYP3A inhibitors
– People with an inability to sense or respond to thirst, or urinate
– Patients with acute hyponatremia

There are more contraindications specific to Jinarc and Samsca. Please notify your doctor or pharmacist of your conditions before being administered with Tolvaptan.

Pharmacist Tips:

– Ensure adequate hydration
– Interrupt the therapy by consulting physicians if hydration is limited

Common dosing schedule:
For those with autosomal dominant polycystic kidney disease, it has to be taken after waking up and 8 hours later. It is suggested to use a device like a schedule to remind yourself to take Tolvaptan after waking up.

For those with chronic hyponatremia with euvolemia or hypervolemia, Tolvaptan is taken daily, and it will be better to take in the morning to prevent nocturia.

This schedule is for reference only, adjustments may be made according to individual needs.

Some common medications Tolvaptan may interact with:
– Digoxin
– Angiotensin II Receptor Blockers, e.g. Candesartan, Irbesartan, Olmesartan
– Topotecan
– Desmopressin
– Cladribine

Tolvaptan may interact with many other medications. Please notify your doctor or pharmacist if you are taking the above medication, dosage adjustments might be needed.

Where to buy Tolvaptan in Hong Kong?

In Hong Kong, Tolvaptan is a prescription only medicine, and requires a prescription from a doctor to be purchased in a pharmacy. It can also be obtained from doctors. To find a pharmacy near you, refer to the list of pharmacies (“Authorized Sellers of Poisons”) from the Hong Kong Department of Health.

For more information about drug names and ingredients, you can visit Hong Kong’s Drug Office at https://www.drugoffice.gov.hk

Need more information?

For detailed information about the use of Tolvaptan in children, pregnancy and breastfeeding, and for questions about drug interactions, please check with your pharmacist or doctor.

Disclaimer: our goal is to provide you with the most relevant drug information and common dosage for Hong Kong. This information does not constitute medical advice. For specific treatment recommendations and advice, always discuss with your doctor or pharmacist, and follow the instructions included with your specific medicine.