title: Commentary on: "Levofloxacin-Induced QTc Prolongation Depends on the Time of Drug Administration".
abstract: Circadian variations in the corrected QT (QTc) interval have been documented in clinical trials. Animal models show circadian variations in expression of the cardiac ion channels that are necessary to maintain the heart's electrophysiological properties. Can these diurnal rhythms in QTc affect the ability of a drug to delay cardiac repolarization?
authors.affiliation: Office of New Drugs, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA. christinegarnett@fda.hhs.gov.
authors.forename: C
authors.initials: C
authors.lastname: Garnett
authors.affiliation: Office of Clinical Pharmacology, Center for Drug Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland, USA.
authors.forename: L
authors.initials: L
authors.lastname: Johannesen
mesh_terms: D000818:Animals; D006801:Humans; D001145:Arrhythmias, Cardiac; D002940:Circadian Rhythm; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004562:Electrocardiography; D006329:Heart Conduction System; D006339:Heart Rate; D064704:Levofloxacin; D008133:Long QT Syndrome
chemical_list: D064704:Levofloxacin