Ingrezza and alcohol

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.

ADJUST DOSE: Coadministration with grapefruit juice may increase the plasma concentration of valbenazine. The mechanism is inhibition of CYP450 3A4-mediated first-metabolism in the gut wall by certain compounds present in grapefruits. The use of valbenazine has been associated with modest prolongation of the QT interval. However, clinically significant QT prolongation may occur in patients taking a strong CYP450 3A4 inhibitor due to increased concentrations of valbenazine and its active metabolite (+)-alfa-dihydrotetrabenazine. In general, the risk of an individual agent or a combination of agents causing ventricular arrhythmia in association with QT prolongation is largely unpredictable but may be increased by certain underlying risk factors such as congenital long QT syndrome, cardiac disease, and electrolyte disturbances (e.g., hypokalemia, hypomagnesemia). The extent of drug-induced QT prolongation is dependent on the particular drugs involved and dosages of the drugs.

MANAGEMENT: Pharmacologic response to valbenazine should be monitored more closely whenever a strong inhibitor of CYP450 3A4 is added to or withdrawn from therapy. Assessment of baseline QT interval and periodic monitoring during therapy may be considered. The manufacturer recommends reducing the dose of valbenazine to 40 mg once daily during concomitant administration with strong CYP450 3A4 inhibitors. Patients should be advised to seek prompt medical attention if they experience symptoms that could indicate the occurrence of torsade de pointes such as dizziness, lightheadedness, fainting, palpitation, irregular heart rhythm, shortness of breath, or syncope. In addition, patients receiving CNS-active agents should be warned of this interaction and advised to avoid or limit consumption of alcohol. Ambulatory patients should be counseled to avoid hazardous activities requiring complete mental alertness and motor coordination until they know how these agents affect them, and to notify their physician if they experience excessive or prolonged CNS effects that interfere with their normal activities.