Skip to Content

Generic Name: tolvaptan (tol VAP tan)
Brand Names: Samsca

What is Samsca?

Samsca (tolvaptan) reduces the level of a hormone that regulates the balance of water and salt (sodium) in the body. High levels of this hormone can cause an imbalance that results in low sodium levels and fluid retention.

Samsca is used to treat hyponatremia (low levels of sodium in your blood) in people with heart failure, and certain hormonal imbalances.

Samsca improves urine flow without causing the body to lose too much sodium as you urinate.

Important information

You should not use Samsca if are unable to urinate, if you are unable to tell when you are thirsty, or if you are severely dehydrated.

You will need to be in a hospital under observation any time you start or restart treatment.

Tell your caregivers at once if you have any of these signs that your hyponatremia is being reversed too quickly: problems with speech or muscle control, trouble swallowing, trouble moving your arms and legs, confusion, or seizure.

While taking Samsca at home, call your doctor if you have signs of liver problems, such as: loss of appetite, upper stomach pain, dark urine, or jaundice (yellowing of the skin or eyes).

Before taking this medicine

You should not use Samsca if you are allergic to tolvaptan, or if you:

  • are unable to urinate;

  • are unable to tell that you are thirsty; or

  • are severely dehydrated and feel like you might pass out.

Some medicines can cause unwanted or dangerous effects when used with Samsca. Your doctor may need to change your treatment plan if you use any of the following drugs:

  • nefazodone;

  • an antibiotic - clarithromycin, telithromycin;

  • antifungal medicine - itraconazole, ketoconazole; or

  • HIV/AIDS medication - indinavir, nelfinavir, ritonavir, saquinavir.

To make sure Samsca is safe for you, tell your doctor if:

  • you have kidney disease or urination problems;

  • you have liver disease (especially cirrhosis);

  • you also take desmopressin (dDAVP), or a diuretic or "water pill";

  • you are malnourished; or

  • you have been drinking large amounts of alcohol.

It is not known whether Samsca will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It is not known whether tolvaptan passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.

How should I take Samsca?

Samsca is usually given once per day. Follow all directions on your prescription label. Your doctor may occasionally change your dose. Do not take this medicine in larger or smaller amounts or for longer than recommended.

You will receive your first few doses in a hospital setting where your heart rhythm can be monitored, in case the medicine causes serious side effects.

Long-term use of tolvaptan can damage your liver or cause death. You should not use tolvaptan for longer than 30 days.

You may take Samsca with or without food.

Take this medicine with a full glass (8 ounces) of water. Drink plenty of fluids during the first 24 hours of taking Samsca, but avoid alcoholic drinks. Follow your doctor's instructions about the type and amount of liquids you should drink while treating hyponatremia. In some cases, drinking too much liquid can be as unsafe as not drinking enough.

Call your doctor if you have ongoing vomiting or diarrhea, or if you are sweating more than usual. You can easily become dehydrated while taking this medication, which can lead to serious side effects.

To be sure this medicine is helping your condition, you may need frequent blood tests.

If you stop taking Samsca for any length of time, do not start taking it again at home. You will need to be in a hospital under observation any time you start or restart treatment with Samsca.

Store at room temperature away from moisture and heat.

Samsca dosing information

Usual Adult Dose for Hyponatremia:

Initial dose: 15 mg orally once a day
Maintenance dose: Increase the dose to 30 mg once a day, after at least 24 hours, to a maximum of 60 mg once a day, as needed to achieve the desired level of serum sodium.
Maximum dose: 60 mg once a day
Duration of therapy: Maximum of 30 days
Comments:
-During initiation and titration, frequently monitor for changes in serum electrolytes and volume.
-Avoid fluid restriction during the first 24 hours of therapy.
-Patients should be advised that they can continue ingestion of fluid in response to thirst.
-Samsca may be dosed without regard to meals.

Uses: Hypervolemic and euvolemic hyponatremia [serum sodium less than 125 mEq/L or less marked hyponatremia that is symptomatic and has resisted correction with fluid restriction], including patients with heart failure, and Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

Usual Adult Dose for Hyponatremia, euvolemic:

Initial dose: 15 mg orally once a day
Maintenance dose: Increase the dose to 30 mg once a day, after at least 24 hours, to a maximum of 60 mg once a day, as needed to achieve the desired level of serum sodium.
Maximum dose: 60 mg once a day
Duration of therapy: Maximum of 30 days
Comments:
-During initiation and titration, frequently monitor for changes in serum electrolytes and volume.
-Avoid fluid restriction during the first 24 hours of therapy.
-Patients should be advised that they can continue ingestion of fluid in response to thirst.
-Samsca may be dosed without regard to meals.

Uses: Hypervolemic and euvolemic hyponatremia [serum sodium less than 125 mEq/L or less marked hyponatremia that is symptomatic and has resisted correction with fluid restriction], including patients with heart failure, and Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

See also: Dosage Information (in more detail)

What happens if I miss a dose?

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while taking Samsca?

Avoid alcoholic drinks.

Grapefruit and grapefruit juice may interact with tolvaptan and lead to unwanted side effects. Avoid the use of grapefruit products while taking Samsca.

Samsca side effects

Get emergency medical help if you have signs of an allergic reaction to Samsca: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Tell your caregivers at once if you have any of these signs that your hyponatremia is being reversed too quickly:

  • problems with speech or muscle control;

  • trouble swallowing;

  • trouble moving your arms and legs;

  • confusion, mood changes; or

  • a seizure.

While taking Samsca at home, call your doctor at once if you have:

  • weakness, or a light-headed feeling (like you might pass out);

  • liver problems - vomiting, loss of appetite, upper stomach pain, tiredness, itching, dark urine, jaundice (yellowing of the skin or eyes); or

  • dehydration symptoms - feeling very thirsty or hot, being unable to urinate, heavy sweating, or hot and dry skin.

Common Samsca side effects may include:

  • dry mouth;

  • increased thirst or urination;

  • hunger, fruity breath odor, drowsiness, blurred vision;

  • constipation; or

  • weakness.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

See also: Side effects (in more detail)

What other drugs will affect Samsca?

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

Many drugs can interact with tolvaptan. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide. Tell your doctor about all your current medicines and any medicine you start or stop using.

Where can I get more information?

  • Your pharmacist can provide more information about Samsca.
  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Samsca only for the indication prescribed.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2017 Cerner Multum, Inc. Version: 4.01.

Date modified: September 05, 2017
Last reviewed: August 03, 2017

Hide