Dabhi Jayesh, Mehta Anita
Department of Pharmacology, L.M. College of Pharmacy, Navarangpura-390 009, Ahmedabad, India.
Curr Drug Saf. 2007 Sep;2(3):200-3. doi: 10.2174/157488607781668873.
The QT interval in electrocardiogram (ECG) reflects the total duration of ventricular myocardial depolarization and repolarization. It has been well recognized that many condition may cause QT interval prolongation. Unfortunately, numbers of cardiac and non-cardiac drug prolong the QT interval and cause a distinctive polymorphic ventricular tachycardia termed torsade de pointes (TdP). TdP can degenerate into ventricular fibrillation, which leads to sudden cardiac death. Recently various regulatory and clinical bodies of Europe, USA, Canada and Australia have made their focus on the drugs that induce prolongation of QT interval. Committee for Proprietary Medicinal Products (CPMP) of the European Agency issued a document entitled 'Points to Consider: The assessment of the potential for QT interval prolongation by non-cardiovascular medicinal products' [1, 2]. In addition, USFDA adopted the guideline 'Clinical evaluation of QT/QTc interval prolongation and proarrhythmic potential for non-anti arrhythmic drugs' [3]. These documents and guidelines are primarily concern with development of novel agents and the new use or new dose of already approved drugs. The scope of this guideline is to study the effect of drugs on QT prolongation and give idea of evaluation of drug's effects on QT prolongation. Today more than 50 available drugs (both old and new) have been identify, which prolong the QT interval [1]. Several drugs have been withdrawn from many countries on this basis but many of these drugs are still available in Indian market and potentially creating life-threatening arrhythmias. This article will focus on recommendation of study on the normal limits of QT interval in Indian population and preparation of the database, which can be helpful in withdrawal of drugs from the market that produces QT prolongation.
心电图（ECG）中的QT间期反映了心室肌去极化和复极化的总持续时间。人们已经充分认识到，许多情况可能导致QT间期延长。不幸的是，许多心脏和非心脏药物会延长QT间期，并引发一种独特的多形性室性心动过速，称为尖端扭转型室速（TdP）。TdP可恶化为心室颤动，进而导致心源性猝死。最近，欧洲、美国、加拿大和澳大利亚的各种监管和临床机构都将重点放在了可导致QT间期延长的药物上。欧洲药品管理局的专有药品委员会（CPMP）发布了一份题为《需考虑的要点：非心血管药品QT间期延长可能性的评估》的文件[1,2]。此外，美国食品药品监督管理局采用了《非抗心律失常药物QT/QTc间期延长及促心律失常潜力的临床评估》指南[3]。这些文件和指南主要关注新型药物的研发以及已批准药物的新用途或新剂量。本指南的范围是研究药物对QT延长的影响，并给出评估药物对QT延长作用的思路。如今，已确定有50多种现有药物（包括新旧药物）会延长QT间期[1]。基于这一原因，许多国家已撤回了几种药物，但其中许多药物在印度市场仍可买到，并可能引发危及生命的心律失常。本文将重点推荐对印度人群QT间期正常范围的研究以及数据库的建立，这有助于从市场上撤回可导致QT延长的药物。
