Effects Of LVFX And AX On I_k Currents In Guinea Pig Ventricular Myocytes

Background and ObjectiveThe fluoroquinolone antibacterial, which is third generation of quinolones demonstrated broad spectrum antimicrobial activity against Gram-negative and Gram-positive bacteria and an excellent tissue distribution, is prescribed for the treatment of many kinds of infection. Development of this drugs , is on going and seeks not only to improve antimicrobial activity but also to reduce adverse event (side action ) ,such as CNS toxicity and photoxicity .However, there are growthing evidence to show that fluoroquinolon antibiotics have been associated with risk of QT prolongation and arrhythmias , which were correlated with a delay of repolarization in cardiac action potential due to a blockade of the human delayed rectifier K⁺ channels (I_k), especially I_Kr, a rapid component of I_k. Recently, sparfloxacin was reported to cause QT interval prolongation while greparfloxacin (GRX) was linked to the life-threatening arrhythmias torsade de pointes (TdP) and withdrawn from clinic use. At this point, the a safety evaluation of fluoroquinolone antibiotics is extreamely necessary and important.Levofloxacin (LVFX) is a member of fluoroquinolone antibiotics that was widely used in clinic while AX is a new member of this family. Synthesized by our own country. It is unknown whether LVFX and AX has a risk of cardiac toxicity like certain fluoroquinolone members that have been known to cause QT prolongation and...