Tolvaptan

Tolvaptan is a prescription medication used in adults to help increase low sodium levels in the blood.

Tolvaptan belongs to a group of drugs called vasopressin receptor blockers. It works by raising salt levels in the blood by removing extra body water as urine.

This medication comes in tablet form and is taken once daily with or without food.

Common side effects of tolvaptan include thirst, dry mouth and constipation.

Tolvaptan is a prescription medication used to help increase low sodium levels in the blood, in adults with conditions such as heart failure and certain hormone imbalances.

This medication may be prescribed for other uses.  Ask your doctor or pharmacist for more information.

Tolvaptan may be found in some form under the following brand names:

• Jynarque

• Samsca

Tolvaptan can cause serious side effects including:

• See "Drug Precautions" section.
• Loss of too much body fluid (dehydration). Tell your healthcare provider if you:
  • have vomiting or diarrhea, and cannot drink normally.
  • feel dizzy or faint. These may be symptoms that you have lost too much body fluid.

Call your healthcare provider right away, if you have any of these symptoms.

The most common side effects of tolvaptan are:

• thirst
• dry mouth
• weakness
• constipation
• making large amounts of urine and urinating often
• increased blood sugar levels

These are not all the possible side effects of tolvaptan. Talk to your healthcare provider about any side effect that bothers you or that does not go away while taking tolvaptan.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements.

These medicines could cause you to have too much tolvaptan in your blood:

• the antibiotic medicines, clarithromycin (Biaxin, Biaxin XL) or telithromycin (Ketek)
• the antifungal medicines, ketoconazole (Nizoral) or itraconazole (Sporonox)
• the anti-HIV medicines, ritonavir (Kaletra, Norvir), indinavir (Crixivan), nelfinavir (Viracept), and saquinavir (Invirase)
• the antidepressant medicine, nefazodone hydrochloride

Tolvaptan may affect the way other medicines work, and other medicines may affect how tolvaptan works.

Know the medicines you take. Keep a list of them and show it to your healthcare provider and pharmacist when you get a new medicine.

This is not a complete list of tolvaptan drug interactions. Ask your healthcare provider or pharmacist for more information.

Do not take tolvaptan if:

• the sodium level in your blood must be increased right away.
• you can not replace fluids by drinking or you can not feel if you are thirsty.
• you are dizzy, faint, or your kidneys are not working normally because you have lost too much body fluid.
• you take certain medicines. See "Drug Interactions" section.
• your body is not able to make urine. Tolvaptan will not help your condition.

Tolvaptan may cause irreversible and potentially fatal liver damage. Tolvaptan should not be taken for more than 30 days. Tell your doctor right away if you develop or have worsening of any of these signs and symptoms of liver problems:

• Loss of appetite, nausea, vomiting
• Fever, feeling unwell, unusual tiredness
• Itching
• Yellowing of the skin or the whites of the eyes (jaundice)
• Unusual darkening of the urine
• Right upper stomach area pain or discomfort

Tolvaptan may make the salt (sodium) level in your blood rise too fast. This can increase your risk of a serious condition called osmotic demyelination syndrome (ODS). ODS can lead to coma or death. ODS can also cause new symptoms such as:

• trouble speaking
• swallowing trouble or feeling like food or liquid gets stuck while swallowing
• drowsiness
• confusion
• mood changes
• trouble controlling body movement (involuntary movement) and weakness in muscles of the arms and legs
• seizures

You or a family member should tell your healthcare provider right away if you have any of these symptoms even if they begin later in treatment. Also tell your healthcare provider about any other new symptoms while taking tolvaptan.

You may be more at risk for ODS if you have:

• liver disease
• not eaten enough for a long period of time (malnourished)
• very low sodium level in your blood
• been drinking large amounts of alcohol for a long period of time (chronic alcoholism)

To lessen your risk of ODS while taking tolvaptan:

• Treatment with tolvaptan should be started and re-started only in a hospital, where the sodium levels in your blood can be checked closely.
• Do not take tolvaptan if you can not tell if you are thirsty.
• To prevent losing too much body water (dehydration), have water available to drink at all times while taking tolvaptan. Unless your healthcare provider tells you otherwise, drink when you are thirsty.
• If your healthcare provider tells you to keep taking tolvaptan after you leave a hospital, it is important that you do not stop and re-start tolvaptan on your own. You may need to go back to a hospital to re-start tolvaptan. Talk to your healthcare provider right away if you stop taking tolvaptan for any reason.
• It is important to stay under the care of your healthcare provider while taking tolvaptan and follow their instructions.

Grapefruit and grapefruit juice may interact with tolvaptan and lead to potentially dangerous effects. Discuss the use of grapefruit products with your healthcare provider..

Tell your healthcare provider about all your medical conditions, including if you:

• have kidney problems and your body can not make urine.
• have liver problems.
• can not feel if you are thirsty.
• have any allergies. 
• are pregnant or breastfeeding.
• are taking desmopressin (dDAVP).

Tell your healthcare provider about all the medicines you take, including prescription and non-prescription medicines, vitamins, and herbal supplements.

Tell your doctor if you are pregnant or plan to become pregnant.

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

This medication falls into category C. In animal studies, pregnant animals were given this medication and had some babies born with problems. No well-controlled studies have been done in humans. Therefore, this medication may be used if the potential benefits to the mother outweigh the potential risks to the unborn child.

Tell your healthcare provider if you are breastfeeding. It is not known if tolvaptan passes into your breast milk. You and your healthcare provider should decide if you will take tolvaptan or breastfeed. You should not do both.

• See "Drug Precautions" section.
• Take tolvaptan exactly as prescribed by your healthcare provider.
• Take tolvaptan tablets by mouth once daily, with or without food..
• Do not drink grapefruit juice during treatment with tolvaptan. This could cause you to have too much tolvaptan in your blood.
• Certain medicines or illnesses may keep you from drinking fluids or may cause you to lose too much body fluid, such as vomiting or diarrhea. If you have these problems, call your healthcare provider right away.
• Do not miss or skip doses of tolvaptan. If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Just take the next dose at your regular time. Do not take 2 doses at the same time.
• If you take too much tolvaptan, call your healthcare provider right away. If you take an overdose of tolvaptan, you may need to go to a hospital.
• If your healthcare provider tells you to stop taking tolvaptan, follow their instructions about limiting the amount of fluid you should drink.

The usual starting dose for tolvaptan is 15 mg taken once daily with or without food.

Your healthcare provider may decide to increase the dose to 30 mg once daily, after at least 24 hours, to a maximum of 60 mg once daily, as needed to achieve the desired level of serum sodium. To minimize the risk of liver problems, you should not take tolvaptan for more than 30 days.

If you take too much tolvaptan, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.

If tolvaptan is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention.

• Store tolvaptan between 59 °F to 86 °F (15 °C to 30 °C).
• Keep tolvaptan and all medicines out of the reach of children.

WARNING: INITIATE AND RE-INITIATE IN A HOSPITAL AND MONITOR SERUM SODIUM

• Tolvaptan should be initiated and re-initiated in patients only in a hospital where serum sodium can be monitored closely.
• Too rapid correction of hyponatremia (e.g., >12 mEq/L/24 hours) can cause osmotic demyelination resulting in dysarthria, mutism, dysphagia, lethargy, affective changes, spastic quadriparesis, seizures, coma and death. In susceptible patients, including those with severe malnutrition, alcoholism or advanced liver disease, slower rates of correction may be advisable.