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. Tolvaptan improves urine flow without causing the body to lose too much sodium as you urinate.
Samsca may also be used for purposes not listed in this medication guide.
Important information
You should not use Samsca if you have cirrhosis or other liver disease, if you are unable to urinate, if you are unable to tell that you are thirsty, or if you are severely dehydrated and feel like you might pass out. Also tell your doctor if you have if you have been drinking large amounts of alcohol, or if you are malnourished.
You will receive your first few doses of Samsca in a hospital setting where your heart rhythm can be monitored, in case the medication causes serious side effects.
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, mood changes, and seizure (convulsions).
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.
Before taking this medicine
You should not use Samsca if you are allergic to tolvaptan, or if you have:
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cirrhosis or other liver disease;
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if you are unable to urinate;
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if you are unable to tell that you are thirsty; or
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if you are severely dehydrated and feel like you might pass out.
Many drugs can interact with Samsca and some should not be used at the same time. Tell your doctor about all other medications you use, especially:
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nefazodone;
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an antibiotic--clarithromycin, telithromycin;
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antifungal medication--itraconazole, ketoconazole, voriconazole;
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hepatitis C medications--boceprevir, telaprevir; or
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HIV/AIDS medication--atazanavir, cobicistat, delavirdine, fosamprenavir, indinavir, nelfinavir, ritonavir, saquinavir.
Your doctor will tell you if any of your medications need to be changed while taking Samsca.
To make sure Samsca is safe for you, tell your doctor about your other medical conditions, especially:
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a history of alcoholism or liver disease;
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kidney disease;
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if you are malnourished; or
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if you have been drinking large amounts of alcohol.
FDA pregnancy category C. It is not known whether Samsca will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant while using this medication.
See also: Pregnancy and breastfeeding warnings (in more detail)
It is not known whether tolvaptan passes into breast milk or if it could harm a nursing baby. You should not breast-feed while you are 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 to make sure you get the best results. Do not take this medicine in larger or smaller amounts or for longer than recommended. Long-term use of Samsca can damage your liver or cause death. You should not use this medicine for longer than 30 days
You will receive your first few doses of Samsca in a hospital setting where your heart rhythm can be monitored, in case the medication causes serious side effects.
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 treatment with Samsca. It is best to drink something as soon as you feel thirsty, 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.
Store at room temperature away from moisture and heat.
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?
Avoid alcoholic drinks.
Grapefruit and grapefruit juice may interact with tolvaptan and lead to unwanted side effects. Discuss the use of grapefruit products with your doctor.
Samsca side effects
Get emergency medical help if you have any of these 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:
Stop using Samsca and call your doctor at once if you have:
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weakness or fainting;
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black, bloody, or tarry stools;
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coughing up blood or vomit that looks like coffee grounds;
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liver symptoms--nausea, upper stomach pain, itching, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes); or
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dehydration (feeling very thirsty or hot, being unable to urinate, heavy sweating, or hot and dry skin).
Common Samsca side effects may include:
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dry mouth;
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increased thirst or urination;
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constipation; or
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loss of appetite, fruity breath odor, drowsiness, dry skin, nausea, vomiting.
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?
Many drugs can interact with tolvaptan. Not all possible interactions are listed here. Tell your doctor about all your medications and any you start or stop using during treatment with Samsca, especially:
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cyclosporine;
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St. John"s wort;
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seizure medication--carbamazepine, phenobarbital, phenytoin; or
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tuberculosis medication--rifabutin, rifampin, rifapentine.
This list is not complete and many other drugs can interact with tolvaptan. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Give a list of all your medicines to any healthcare provider who treats you.
