Drug Interaction Report

Using berotralstat together with tolvaptan may increase the blood levels and effects of both drugs. It may also increase the risk of an irregular heart rhythm that may be serious and potentially life-threatening, although it is a relatively rare side effect. Your doctor may be able to prescribe alternatives that do not interact, or you may need a dose adjustment or more frequent monitoring to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects. You should seek immediate medical attention if you develop sudden dizziness, lightheadedness, fainting, shortness of breath, or heart palpitations during treatment with these medications. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

You should avoid drinking grapefruit juice during treatment with tolvaptan. Grapefruit juice can cause too much of the medication to be in the blood. Serious nervous system side effects such as difficulty swallowing, trouble speaking, muscle weakness, trouble controlling body movements, confusion, mood changes, seizures, and coma may occur. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.