Effects of probucol, a typical hERG expression inhibitor, on in vivo QT interval prolongation in conscious dogs

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• 作者：Hisashi Nogawa ; Tomoyuki Kawai ; Miho Yajima ; Masahiro Miura ; Tetsurou Ogawa ; Kouji Murakami
• 关键词：Probucol ; hERG expression inhibitor ; QT interval prolongation ; Conscious dogs
• 刊名：European Journal of Pharmacology
• 出版年：15 November, 2013
• 年：2013
• 卷：720
• 期：1-3
• 页码：29-37
• 全文大小：1851 K

文摘

The cholesterol-lowering drug, probucol, is known to induce QT interval prolongation and torsades de pointes in patients. Recent in vitro studies have indicated that probucol reduces hERG expression in the plasma membrane and does not directly block human ether-a-go-go-related gene (hERG) channels. The present study was performed to investigate the effects of probucol on in vivo QT interval prolongation. Epicardial electrocardiograms were recorded in conscious dogs given oral single or repeated (7 days) doses of probucol (100 mg/kg), and in combination with moxifloxacin (20 mg/kg). QTc intervals were analyzed by a probabilistic method with individual rate collection formulae. Values of change in QTc (<DELTA>QTc) interval and its integration from 1 to 21 h (AUC_1-21 h) were calculated to evaluate drug-induced QT prolongation. A single dose of probucol slightly but significantly increased the AUC_1-21 h QTc interval on days 2 and 3. The QT prolongation was markedly augmented by repeated doses of probucol in a time-dependent manner, despite the lack of increase in plasma concentration. The combination of probucol and moxifloxacin produced additive effects on QT interval prolongation. These results suggest that long-term exposure to the hERG expression inhibitor, probucol, is required to evaluate its maximal effects on in vivo QT interval prolongation. A combination of direct and indirect hERG inhibitors may produce simple additive effects on QT interval prolongation.