title: Dynamic QT/RR relationship of cardiac conduction in premature infants treated with low-dose doxapram hydrochloride.
abstract: Doxapram hydrochloride, a respiratory stimulant, has several undesirable side effects during high-dose administration, including second-degree atrioventricular (AV) block and QT prolongation. In Japan, this drug is contraindicated for newborn infants. Recent studies, however, have demonstrated the efficacy and safety of doxapram therapy for apnea of prematurity (AOP) using lower doses than those previously tested. As a result, approximately 60% of Japanese neonatologists continue to use this drug. This study used surface ECG recordings to assess the cardiac safety of low-dose doxapram hydrochloride (0.2 mg/kg/h) in fifteen premature very-low-birth-weight infants with idiopathic AOP. Cardiac intervals and number of apnea episodes were compared before and after drug administration. Low-dose doxapram hydrochloride resulted in approximately 90% reduction in the frequency of apnea without side effects. None of the infants developed QT or PR prolongation, arrhythmia, or other conduction disorders. In addition, there was no change in the slope of QT/RR before versus after administration of doxapram hydrochloride. We conclude that low-dose administration of doxapram hydrochloride did not have any undesirable effects on myocardial depolarization and repolarization.
authors.affiliation: Department of Pediatrics, School of Medicine, Fujita Health University Toyoake, Aichi, Japan. m-miata@jc4.so-net.ne.jp
authors.forename: Masafumi
authors.initials: M
authors.lastname: Miyata
authors.forename: Tadayoshi
authors.initials: T
authors.lastname: Hata
authors.forename: Noriko
authors.initials: N
authors.lastname: Kato
authors.forename: Masatomo
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Hiroko
authors.initials: H
authors.lastname: Mizutani
authors.forename: Masamichi
authors.initials: M
authors.lastname: Kubota
authors.forename: Toshio
authors.initials: T
authors.lastname: Yamazaki
mesh_terms: D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000009:adverse effects; D004315:Doxapram / Q000008:administration & dosage / Q000009:adverse effects*; D004562:Electrocardiography; D006329:Heart Conduction System / Q000187:drug effects* / Q000503:physiopathology*; D006801:Humans; D007230:Infant, Low Birth Weight / Q000502:physiology; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D019102:Infant, Very Low Birth Weight / Q000502:physiology; D019141:Respiratory System Agents / Q000008:administration & dosage / Q000009:adverse effects; D020182:Sleep Apnea, Central / Q000188:drug therapy
chemical_list: D000697:Central Nervous System Stimulants; D019141:Respiratory System Agents; D004315:Doxapram