A review paper of all available clinical studies in 2017 found that, although valbenazine may prolong the QTc interval, especially in patients who are poor CYP2D6 metabolizers or those taking concomitant medications that either prolong QTc interval or cause CYP2D6 inhibition, there were no clinically significant alterations in EKG results of participants in clinical trials, including in patients who were taking medications known to prolong the QTc interval potentially. In an analysis of two studies of healthy male volunteers, no changes to the QTc interval were noted. An analysis of the pooled data from all three KINECT trials as well as the 48-week extension period of the KINECT 3 trial found that there was no statistically significant difference in the number of cardiac-related TEAEs between any dose of valbenazine and placebo. In the 6-week double-blind, placebo-controlled trial, there were a total of five cardiac-related TEAEs, including myocardial infarction in one participant in the placebo arm of the trial and sudden death possibly resulting from a cardiovascular event in one participant with multiple cardiac risk factors in the 80 mg valbenazine group. Other cardiac-related TEAEs were chest pain (n=1, 40 mg valbenazine), bradycardia (n=1, 40 mg valbenazine), and increased blood pressure (n=1, 80 mg valbenazine). Additionally, at week 6, there was no statistically significant difference in QTc prolongation between either active drug arm and placebo. Those who took valbenazine 40 mg daily showed a 1.1ms mean change, valbenazine 40 mg daily showed a 2.1ms mean change, and placebo showed a 1.3ms mean change; all p-values were >0.05. In the KINECT 3 extension period, three cardiac-related TEAEs were leading to discontinuation (syncope, n=2, 1 in each arm; cardiac failure, n=1, 8 0mg valbenazine), and the most common cardiac TEAEs were chest pain (n=4, 2 in each arm) and syncope (n=3, 40 mg; n=1, 80 mg). Further, although more participants in the 80 mg group had a QTc increase >30ms from baseline (24%) or a QTc >450ms (22%) than in the 40 mg group (14.7% and 13.7%, respectively), few participants had a significant increase in QTc (>60ms increase from baseline) or a QTc >480ms. There was no significant difference between the 40mg and 80mg groups: QTc >60mg increase 3.2% and 3.0%, respectively, and QTc >480ms 2.1% and 3.0%, respectively. Finally, subgroup analyses revealed no exacerbating effects of valbenazine on QTc prolongation in the population already taking medications known to prolong QTc (74.3% of the pooled study populations). Mean QTc values for this group were 411.2ms, 414ms, and 413ms at baseline and 412.2ms, 413.7ms, and 413.6ms at week 6 for placebo, 40 mg valbenazine, and 80 mg valbenazine, respectively. This difference was not statistically different from those for the group not taking concomitant medications known to prolong QTc: 414.1ms, 416.3ms, 412.6ms at baseline, and 417.9ms, 418.7ms, and 418.3ms at week 6 for placebo, 40mg valbenazine, and 80mg valbenazine, respectively. No analysis of QTc prolongation in patients who are poor CYP2D6 metabolizers was performed due to the low number of study participants with that characteristic (4.8% of study participants). At this time, CYP genotyping is not required or recommended for patients who might be prescribed valbenazine. summarizes the studies discussed in this section., Learn about the side effects of Ingrezza (valbenazine), from common to rare, for consumers and healthcare professionals., Objective:To explore the long-term effects of once-daily valbenazine on tardive dyskinesia (TD). Background:Valbenazine (INGREZZA®) was approved for TD based on several short-term placebo-controlled trials, a blinded extension study, and the long-term .