This randomized, placebo-controlled, double-blind, outpatient study evaluat
ed the effects of prolonged exposure to foul times the recommended daily do
se of loratadine on electrocardiographic (ECG) parameters, including the QT
(c) interval. Seventy adult men received either loratadine 40 mg once daily
or placebo for 13 weeks. The primary safety variable was ECG parameters re
corded at weeks 3, 5, 7, and 9, and 1 month after the final dose. No statis
tically significant mean change from baseline in any ECC parameter or indiv
idual trends suggesting QT(c) prolongation were observed. No patient had a
QT(c) interval greater than 440 msec at any time point. Loratadine was well
tolerated, and there were no reports of dizziness or syncope. Long-term ad
ministration of loratadine 40 mg once daily was well tolerated and produced
no evidence of QT(c) interval prolongation or any other cardiac arrhythmia
s.