Samsca is an oral tablet that 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.

This medication guide provides information about the Samsca brand of tolvaptan. Jynarque is another brand of tolvaptan that is not covered in this medication guide.

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

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

If you have polycystic kidney disease, do not use Samsca. You should be prescribed another brand of tolvaptan (Jynarque) through a special program that ensures laboratory monitoring of your liver.

Samsca is given to treat low levels of sodium in your blood, but can be dangerous if this condition is reversed too quickly. Tell your caregivers at once if you have problems with speech or muscle control, trouble swallowing, trouble moving your arms and legs, confusion, or seizure.

Tolvaptan can cause serious or fatal liver problems. Call your doctor right away if you don't feel well and you have right-sided upper stomach pain, vomiting, loss of appetite, or yellowing of your skin or eyes.

You will need frequent medical tests before and during treatment with Samsca.

Tell your doctor about all your current medicines and any you start or stop using. Many drugs can interact, and some drugs should not be used together.

Take Samsca tablets exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets.

Drink plenty of fluids while taking Samsca, but do not drink grapefruit juice or alcoholic drinks.

You may take the tablet with or without food.

Samsca is usually taken once per day. Follow your doctor's dosing instructions very carefully.

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

Long-term use of tolvaptan can damage your liver. You should not use this medicine for longer than 30 days.

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

You will need frequent medical tests.

Store at room temperature away from moisture and heat.

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.

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 receiving Samsca should be advised that they can continue ingestion of fluid in response to thirst.

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)

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

• you are unable to urinate;

• you are unable to tell that you are thirsty; or

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

You should not take Samsca if your sodium level needs to be increased quickly.

Some medicines can cause unwanted or dangerous effects when used with Samsca. Your doctor may change your treatment plan if you also use:

• 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 ever had:

• kidney disease or urination problems;

• liver problems;

• allergies;

• if you drink large amounts of alcohol;

• if you are malnourished; or

• if you also use desmopressin (dDAVP), or a diuretic or "water pill."

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant.

You should not breastfeed while using Samsca.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not use two doses at one time.

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

Avoid alcoholic drinks.

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

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.

Call your doctor at once if you have:

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

• irregular heartbeats;

• unexplained weight loss;

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

• liver problems - right-sided upper stomach pain, vomiting, loss of appetite, fever, itching, yellowing of your skin or eyes, not feeling well.

Samsca is given to treat low levels of sodium in your blood, but can be dangerous if your sodium level rises too fast. Tell your doctor or 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.

Common Samsca side effects may include:

• dry mouth;

• increased thirst or urination;

• hunger, fruity breath odor;

• 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.

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, and some drugs should not be used at the same time. Tell your doctor about all your current medicines and any medicine you start or stop using. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here.