Tolvaptan (By mouth)

Introduction

Tolvaptan (tol-VAP-tan)

Treats hyponatremia (low amount of sodium in the blood).

Brand Name(s)

Samsca

There may be other brand names for this medicine.

When This Medicine Should Not Be Used

You should not use this medicine if you have had an allergic reaction to tolvaptan, or if you are not able to pass urine (anuria) or can not tell if you are thirsty. You should 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

Tablet

  • Your doctor will tell you how much of this medicine to use and how often. Your dose may need to be changed several times in order to find out what works best for you. Do not use more medicine or use it more often than your doctor tells you to.
  • You may take this medicine with or without food.
  • This medicine should come with a Medication Guide. Read and follow these instructions carefully. Ask your doctor or pharmacist if you have any questions. Ask your pharmacist for the Medication Guide if you do not have one.

If a dose is missed:

  • If you miss a dose or forget to use your medicine, use it as soon as you can. If it is almost time for your next dose, wait until then to use the medicine and skip the missed dose. Do not use 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  • Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any outdated medicine or medicine no longer needed.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 away from children and 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.

  • Make sure your doctor knows if you are also using aprepitant (Emend®), carbamazepine (Tegretol®), cyclosporine (Neoral®, Sandimmune®), diltiazem (Cardizem®), erythromycin (Ery-Tab®), fluconazole (Diflucan®), phenobarbital (Luminal®), phenytoin (Dilantin®), rifabutin (Mycobutin®), rifampin (Rifadin®, Rimactane®), rifapentin (Priftin®), St. John's wort, or verapamil (Isoptin®). Tell your doctor if you are also using potassium supplements.
  • 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, poor nutrition (undernourished), dehydration, stomach bleeding problems, or high potassium in the blood. Tell your doctor if you have been drinking large amounts of alcohol for a long period of time.
  • Check with your doctor right away if you have drowsiness; confusion; mood changes; muscle weakness in the arms or legs; seizures (convulsions); or trouble with speaking, swallowing, or controlling body movements. These may be symptoms of a serious and rare condition called osmotic demyelination syndrome (ODS). This may occur if the sodium blood level rises too fast.
  • 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 need to check your blood at regular visits while you are using this medicine. Be sure to keep all appointments.

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
  • Chest pain or troubled breathing.
  • Confusion, weakness, uneven heartbeat, shortness of breath, or numbness or tingling in your hands, feet, or lips.
  • Fainting or dizziness.
  • Fast, slow, or irregular heartbeat.
  • Fever.
  • Increase in how much or how often you urinate.
  • Increased hunger or thirst.
  • Muscle pain, tenderness, or weakness.
  • Pain, redness, or swelling in your arm or leg.
  • Red or black stools.
  • Red or dark brown urine.
  • Vomiting of blood or material that looks like coffee grounds.

If you notice these less serious side effects, talk with your doctor:

  • Constipation, nausea, or loss of appetite.
  • Dry mouth.
  • Lack or loss of strength.

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

Version Info

  • Last Reviewed on 06/12/2013

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This page was last updated: June 18, 2013

         
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