title: Acute hypokalemia may not be an effective way to sensitize the in situ canine heart for sparfloxacin-induced long QT syndrome.
abstract: Extents of the sparfloxacin (3 - 10 mg/kg, i.v.)-induced QT interval prolongation under normokalemic and hypokalemic conditions were assessed in halothane-anesthetized beagle dogs (n = 5). The hypokalemic condition was induced by an oral administration of furosemide (200 mg/kg per day) for 3 days, which decreased the serum potassium concentration from 3.65 +/- 0.13 to 2.35 +/- 0.13 mM (P < 0.05). However, the decrease of potassium concentration by itself did not affect the extent of the sparfloxacin-induced QT interval prolongation. These results indicate that acute hypokalemia may not severely sensitize the in situ heart for drug-induced long QT syndrome as previously thought.
authors.affiliation: New Product Research Laboratories II, Daiichi Pharmaceutical Co., Ltd., Tokyo, Japan.
authors.forename: Katsuyoshi
authors.initials: K
authors.lastname: Chiba
authors.forename: Atsushi
authors.initials: A
authors.lastname: Sugiyama
authors.forename: Kazuo
authors.initials: K
authors.lastname: Watanabe
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Takasuna
authors.forename: Keitaro
authors.initials: K
authors.lastname: Hashimoto
mesh_terms: D000818:Animals; D000995:Antitubercular Agents / Q000633:toxicity; D004285:Dogs; D004353:Drug Evaluation, Preclinical; D005260:Female; D024841:Fluoroquinolones / Q000633:toxicity*; D005665:Furosemide; D006329:Heart Conduction System / Q000187:drug effects; D007008:Hypokalemia / Q000139:chemically induced; D008133:Long QT Syndrome / Q000209:etiology*; D023421:Models, Animal; D013997:Time Factors
chemical_list: D000995:Antitubercular Agents; D024841:Fluoroquinolones; D005665:Furosemide; C061363:sparfloxacin