Active Ingredient: DOXEPINE
While thorough QT studies don't find a QT prolongation following a single Doxepine dose In a 6-week randomized, double-blind parallel group study of 40 patients with major depressive disorder comparing doxepin to fluoxetine, electrocardiographic parameters were assessed using high-resolution signal-averaged ECGs. Doxepin therapy was associated with a statistically significant prolongation of the rate-corrected QT interval increasing from 417 +/- 36ms to 439 +/- 28 ms (p < 0.03) after 6 weeks. While overall QRS duration was not broadly prolonged, a strong positive correlation was established between serum doxepin concentrations and ventricular depolarization slowing (r = 0.78, p < 0.0001). Doxepin also significantly increased heart rate (69 +/- 12 to 81 +/- 13 BPM, p = 0.0003),
https://doi.org/10.1097/00004714-199702000-00004, https://doi.org/10.1016/j.clinthera.2011.05.092, https://doi.org/10.7326/0003-4819-135-5-200109040-00026