What is tolvaptan?
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.
Tolvaptan 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.
Tolvaptan may also be used for purposes not listed in this medication guide.
You will need to be in a hospital under observation any time you start or restart treatment with tolvaptan.
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.
Tell your caregivers at once if you have 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 tolvaptan 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 tolvaptan if you are allergic to it, or if:
- you are unable to urinate;
- you are unable to tell that you are thirsty;
- you are severely dehydrated and feel like you might pass out; or
- you have autosomal dominant polycystic kidney disease (unless you receive tolvaptan through a special program that includes frequent liver function tests).
Some medicines can cause unwanted or dangerous effects when used with tolvaptan. Your doctor may change your treatment plan if you also use:
- an antibiotic–clarithromycin, telithromycin;
- antifungal medicine–itraconazole, ketoconazole; or
- HIV/AIDS medication–indinavir, nelfinavir, ritonavir, saquinavir.
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 tolvaptan will harm an unborn baby. Tell your doctor if you are pregnant.
It may not be safe to breast-feed while using this medicine. Ask your doctor about any risk.
How should I take tolvaptan?
You will receive your first dose in a hospital or clinic setting to quickly treat any serious side effects.
Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.
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 tolvaptan 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 tolvaptan, but avoid alcoholic drinks. Follow your doctor’s instructions about the type and amount of liquids you should drink while treating hyponatremia.
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.
You will need frequent medical tests.
Store at room temperature away from moisture and heat.
If you stop taking tolvaptan 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 tolvaptan.
What happens if I miss a dose?
Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.
What should I avoid while taking tolvaptan?
Avoid alcoholic drinks.
Grapefruit may interact with tolvaptan and lead to unwanted side effects. Avoid the use of grapefruit products.
Tolvaptan side effects
Get emergency medical help if you have signs of an allergic reaction: 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 tolvaptan at home, call your doctor at once if you have:
- weakness, or a light-headed feeling (like you might pass out);
- liver problems–right-sided upper stomach pain, vomiting, loss of appetite, yellowing of your skin or eyes, not feeling well; or
- dehydration symptoms–feeling very thirsty or hot, being unable to urinate, heavy sweating, or hot and dry skin.