Tolvaptan (By mouth)
Treats hyponatremia (low sodium levels in the blood).
SamscaThere may be other brand names for this medicine.
When This Medicine Should Not Be Used:
Do not use this medicine if you have had an allergic reaction to tolvaptan. Do not use this medicine if you are not able to pass urine or cannot tell if you are thirsty. Do not use this medicine if you are also taking clarithromycin (Biaxin®), indinavir (Crixivan®), itraconazole (Sporanox®), ketoconazole (Nizoral®), nefazodone (Serzone®), nelfinavir (Viracept®), ritonavir (Norvir®), saquinavir (Fortovase®, Invirase®), or telithromycin (Ketek®).
How to Use This Medicine:
- Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
- You need to start or restart this medicine while you are in the hospital. Your health caregivers need to monitor the sodium levels in your blood. This will allow your doctor to check if this medicine is working well and monitor any unwanted problems that may occur.
- This medicine might make you urinate more than usual, so you need to drink water whenever you feel thirsty. You need to stay hydrated.
- This medicine is not for long-term use. Most people should not take this medicine for more than 30 days.
- This medicine should come with a Medication Guide. Ask your pharmacist for a copy if you do not have one.
If a dose is missed:
- Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
How to Store and Dispose of This Medicine:
- Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.
- Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.
- Keep all medicine out of the reach of children. Never share your medicine with anyone.
Drugs and Foods to Avoid:
Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
- You should not use this medicine together with hypertonic saline, unless your doctor tells you otherwise.
- Make sure your doctor knows if you are also using St John's wort, aprepitant (Emend®), carbamazepine (Tegretol®), cyclosporine (Gengraf®, Neoral®, Sandimmune®), desmopressin (dDAVP), digoxin (Lanoxin®), diltiazem (Cardizem®), erythromycin (Ery-Tab®), fluconazole (Diflucan®), phenobarbital (Luminal®), phenytoin (Dilantin®), rifabutin (Mycobutin®), rifampin (Rifadin®, Rimactane®), rifapentine (Priftin®), a diuretic (water pill, such as spironolactone, triamterene, Aldactone®), or certain blood pressure medicines (such as verapamil, Isoptin®), benazepril, enalapril, lisinopril, Avalide®, Avapro®, Benicar®, Cozaar®, Diovan®, Lotrel®, Micardis®, Vasotec®, Zestoretic®, Zestril®).
- Ask your doctor first before you use any medicine or salt substitute that contains potassium.
- Do not drink alcohol while you are using this medicine.
- Do not eat grapefruit or drink grapefruit juice while you are using this medicine.
Warnings While Using This Medicine:
- Make sure your doctor knows if you are pregnant or breastfeeding, or if you have kidney disease, liver disease (including cirrhosis), dehydration, or high potassium levels in the blood. Tell your doctor if you have trouble eating enough or might be malnourished. Also tell your doctor if you drink alcohol every day or in large amounts.
- Check with your doctor right away if you feel sleepy, confused, moody, or weak, or if you have a seizure or trouble talking, swallowing, or controlling body movements. These symptoms may mean your sodium blood level is rising too fast.
- Check with your doctor right away if you have pain or tenderness in the upper stomach, pale stools, dark urine, loss of appetite, nausea, vomiting, or yellow eyes or skin. These could be symptoms of a serious liver problem.
- Certain medicines or illnesses, such as vomiting or diarrhea, may cause you to lose too much body water (dehydration). If you think you are dehydrated, tell your doctor right away. Always have water available to drink if you are thirsty, unless your doctor tells you otherwise.
- Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.
- Tell your doctor if you stop taking this medicine. You may need to limit how much water and other beverages you drink. You should never start taking this medicine again on your own. You must do that in a hospital where your sodium levels can be tested.
Possible Side Effects While Using This Medicine:
Call your doctor right away if you notice any of these side effects:
- Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
- Confusion, weakness, trouble breathing, numbness or tingling in your hands, feet, or lips
- Dark-colored urine or pale stools, nausea, vomiting, loss of appetite, pain in your upper stomach, yellow skin or eyes
- Fainting or dizziness
- Feeling like something is stuck in your throat
- Trouble controlling body movement and weakness in the arms or legs
- Trouble talking or swallowing
- Urinating less or less often than normal
- Vomiting, diarrhea
If you notice these less serious side effects, talk with your doctor:
- Constipation, nausea, or loss of appetite
- Dry mouth
- Mild weakness
If you notice other side effects that you think are caused by this medicine, tell your doctor
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088
Last Updated: 3/4/2018
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