Drug Interactions between PCE Dispertab and valbenazine

Grapefruit and grapefruit juice may increase the blood levels and effects of valbenazine, such as drowsiness and an irregular heart rhythm problem called QT prolongation. Irregular heart rhythm problems may be serious and potentially life-threatening, although it is a relatively rare side effect. You may be more susceptible if you have a heart condition called congenital long QT syndrome, other cardiac diseases, conduction abnormalities, or electrolyte disturbances (for example, magnesium or potassium loss due to severe or prolonged diarrhea or vomiting). Talk to your doctor if you have questions or concerns. Do not add grapefruit products to your diet, or increase or decrease the amount currently in your diet without first talking to your doctor. You may need a dose adjustment of valbenazine or more frequent monitoring by your doctor to safely use both valbenazine and grapefruit products. 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.

Food decreases the levels of erythromycin in your body. Take erythromycin on an empty stomach at least 30 minutes before or 2 hours after a meal. This will make it easier for your body to absorb the medication. However, some erythromycin products may be taken without regard to meals. Ask your healthcare provider about your particular prescription if you are uncertain of how to take it. Grapefruits and grapefruit juice may increase erythromycin levels but how this may affect you is not known. Do not increase or decrease the amount of grapefruit products in your diet without first talking to your doctor.

Information for this minor interaction is available on the professional version.