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Uses

What is tolvaptan used for?

Tolvaptan is commonly used to treat low sodium levels (hyponatremia).

Tolvaptan may also be used for other conditions as determined by your healthcare provider.

A different form of tolvaptan can be used to treat a certain type of kidney condition called autosomal dominant polycystic kidney disease (ADPKD). See Jynarque (tolvaptan) for more information.

How does tolvaptan work (mechanism of action)?

Tolvaptan blocks a substance in the body called vasopressin from binding to the vasopressin V2-receptor in the kidneys. When this receptor is blocked, the body gets rid of more water through the urine. This decreases the total amount of water in the body and increases sodium levels.

How is tolvaptan supplied (dosage forms)?

Brands and other names

  • Samsca

Dosage forms and strengths

  • 15 mg, 30 mg, 60 mg  oral tablets

How should I store tolvaptan?

Tolvaptan should be stored at room temperature, between 68 F to 77 F (20 C to 25 C). It can be exposed to temperatures between 59 F to 86 F (15 C to 30 C) for shorter periods of time, such as when transporting it. Store in a cool, dry place.

Side Effects

What are the most common side effects of tolvaptan?

The most common side effects of tolvaptan are listed below. Tell your healthcare provider if you have any of these side effects that bother you.

  • Feeling thirsty
  • Dry mouth
  • Feeling weak or low in energy
  • Constipation
  • Peeing more than usual
  • High blood glucose levels (hyperglycemia)

There may be other side effects of tolvaptan that are not listed here. Contact your healthcare provider if you think you are having a side effect of a medicine. In the U.S., you can report side effects to the FDA at www.fda.gov/medwatch or by calling 800-FDA-1088. In Canada, you can report side effects to Health Canada at www.health.gc.ca/medeffect or by calling 866-234-2345.

What are the serious side effects of tolvaptan?

While less common, the most serious side effects of tolvaptan are described below, along with what to do if they happen.

Severe Allergic Reactions. Tolvaptan may cause allergic reactions, which can be serious. Stop taking tolvaptan and get help right away if you have any of the following symptoms of a serious allergic reaction.

  • Breathing problems or wheezing
  • Racing heart
  • Fever or general ill feeling
  • Swollen lymph nodes
  • Swelling of the face, lips, mouth, tongue, or throat
  • Trouble swallowing or throat tightness
  • Itching, skin rash, or pale red bumps on the skin called hives
  • Nausea or vomiting
  • Dizziness, feeling lightheaded, or fainting
  • Stomach cramps
  • Joint pain

Central pontine myelinolysis. Central pontine myelinolysis, also known as osmotic demyelination syndrome (ODS), is a serious condition that occurs when sodium levels are increased too quickly in a person with low sodium levels. Certain people may have a higher risk of developing this condition, including people with liver problems, poor appetite and nutrition, or those who drink large amounts of alcohol. To reduce the risk of this happening, tolvaptan will be started while you are admitted to the hospital. Let your healthcare provider know right away if you have any of the following symptoms of this condition.

  • Confusion
  • Changes in mood
  • Drowsiness
  • Weak muscles
  • Seizures
  • Tremors
  • Trouble moving your arms or legs
  • Trouble speaking or swallowing

Liver Damage. Liver damage, also called hepatotoxicity, can happen when taking tolvaptan. This risk increases with longer use of the medicine. Call your healthcare provider right away if you have any of the following symptoms of liver damage.

  • Nausea or vomiting
  • Stomach or belly pain
  • Fever
  • Weakness or unusual tiredness
  • Itching
  • Loss of appetite
  • Dark-colored urine (pee)
  • Your skin or the whites of your eyes turning yellowish in color (also called jaundice)

Dehydration. Tolvaptan may cause dehydration. Dehydration may lead to low blood pressure, especially when you stand up (orthostatic hypotension), or kidney damage. This is more likely to happen in people who are taking certain medicines, such as diuretics, or who have been told to limit the amount of fluids they drink. Call your healthcare provider right away if you have any of the following symptoms of dehydration or low blood pressure.

  • Dizziness or lightheadedness
  • Weakness or unusual tiredness
  • Unsteadiness

High Potassium Level (Hyperkalemia). Tolvaptan can cause a high potassium level, which can be serious and may lead to death. Your healthcare provider may check your potassium levels, especially if you take certain other medicines. Call your healthcare provider right away if you have any of the following symptoms of a high potassium level.

  • Nausea or vomiting
  • Trouble breathing
  • Muscle weakness or unusual tiredness
  • Slow heartbeat or feeling of skipped heartbeats
  • Abnormal heart rhythm
     

Warnings & Precautions

Who should not use tolvaptan?

Allergies to Ingredients. People who are allergic to any of the following should not take tolvaptan.

  • Samsca
  • Tolvaptan
  • Any of the ingredients in the specific product dispensed

Your pharmacist can tell you all of the ingredients in the specific tolvaptan products they stock.

Autosomal Dominant Polycystic Kidney Disease (ADPKD). People with this condition must use a different form of this medicine due to the need for safety monitoring. See Jynarque (tolvaptan) for more information.

Dehydration. People who are dehydrated or who have low levels of fluid in their bodies should not use tolvaptan.

Drug Interactions. Tolvaptan should not be taken while you are using certain other medicines. Before using tolvaptan, tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.  See the Interactions section for more details.

Problems Peeing or Bladder Blockage. People who have trouble peeing should not use tolvaptan until this issue has been corrected. Reasons that a person may not be able to pee include kidney disease or a blockage in the urinary tract, which can be caused by an injury, an infection, or a kidney stone.

Unable to Sense or Respond to Thirst. People who cannot tell whether they are thirsty should not use tolvaptan. Similarly, people who are not able to drink fluids regularly throughout the day when they are thirsty should not use tolvaptan.

What should I know about tolvaptan before using it?

Do not take tolvaptan unless it has been prescribed to you by a healthcare provider. Take it as prescribed.

Do not share tolvaptan with other people, even if they have the same condition as you. It may harm them.

Keep tolvaptan out of the reach of children.

Tolvaptan can cause you to pee more often, which may increase your risk of becoming dehydrated. It is important that you drink fluids regularly while taking this medicine. Let your healthcare provider know if you have been told to limit the amount of fluids that you drink each day. This may increase your risk of becoming dehydrated. 

This medicine can change the sodium levels in your blood very quickly. In order to monitor your sodium levels closely, you will only start tolvaptan while you are in the hospital. If your healthcare provider tells you to keep taking tolvaptan after you leave the hospital, be careful not to miss a dose. It may not be safe to stop and restart the medicine at home. If you stop taking the medicine for any reason, speak with your healthcare provider before restarting it. You may need to be readmitted to the hospital in order to restart the medicine.

What should I tell my healthcare provider before using tolvaptan?

Tell your healthcare provider about all of your health conditions and any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using. This will help them determine if tolvaptan is right for you.

In particular, make sure that you discuss any of the following.

Current and Past Health Conditions. Tell your healthcare provider if you have any of the following.

  • Alcohol use disorder
  • An illness that causes vomiting or diarrhea
  • Dehydration
  • High potassium levels
  • Kidney problems
  • Liver problems
  • Problems peeing or bladder blockage
  • Unable to tell when you are thirsty
  • Unable to drink fluids throughout the day

Pregnancy. It is not known if or how tolvaptan could affect pregnancy or harm an unborn baby. Tell your healthcare provider if you are or plan to become pregnant. Your healthcare provider will advise you if you should take tolvaptan while you are pregnant or trying to get pregnant.

Breastfeeding. It is not known if tolvaptan passes into breast milk. Tell your healthcare provider if you are breastfeeding or plan to breastfeed. Your healthcare provider will advise you if you should stop breastfeeding or stop taking tolvaptan.

Interactions

Does tolvaptan interact with foods or drinks?

You should not eat grapefruit or drink grapefruit juice while taking tolvaptan. Grapefruit or grapefruit juice can cause a dangerous increase in the blood levels of tolvaptan.

It is unknown if drinking alcohol will affect tolvaptan. The risk of dehydration may be increased if you drink alcohol while taking tolvaptan.

Does tolvaptan interact with other medicines (drug interactions)?

Always tell your healthcare provider about any prescription or over-the-counter (OTC) medicines, vitamins/minerals, herbal products, and other supplements you are using.

In particular, make sure that you discuss if you are using any of the following:

  • An angiotensin-converting enzyme (ACE) inhibitor, such as enalapril or lisinopril, which is a medicine for high blood pressure, heart failure, and certain kidney problems
  • An angiotensin II receptor blocker (ARB), such as losartan or valsartan, which is a medicine for high blood pressure, heart failure, and other heart conditions
  • Amiloride (Midamor), eplerenone (Inspra), triamterene (Dyrenium), or spironolactone (Aldactone, Carospir), which is a type of diuretic, also called a water pill
  • Clarithromycin, which is a medicine used for bacterial infections 
  • Ketoconazole or itraconazole (Sporanox, Tolsura), which is a medicine used for fungal infections
  • Ritonavir (Norvir), lopinavir/ritonavir (Kaletra), or nelfinavir (Viracept),  which is a medicine commonly used to treat HIV
  • Nefazodone, which is a medicine commonly used for depression
  • Desmopressin (DDAVP), which is a medicine used to treat a condition called diabetes insipidus

Many other medicines may alter the blood levels of tolvaptan. Tell your healthcare provider about all medicines that you take or have recently taken.

This may not be a complete list of medicines that can interact with tolvaptan. Always check with your healthcare provider.

Does interact with other drugs you are taking?

Enter your medication into the WebMD interaction checker

Overdose/Missed Dose

What should I do if I accidentally use too much tolvaptan?

If you or someone else has used too much tolvaptan, get medical help right away, call 911, or contact a Poison Control center at 800-222-1222.

What should I do if I miss a dose of tolvaptan?

It is important that you do not miss doses of this medicine. If you do miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and only take the next dose. Do not take double or extra doses.