A retrospective cohort study among US veterans showed that compared with amoxicillin, both azithromycin and levofloxacin were associated with elevated risks of death and serious cardiac arrhythmias during standard treatment period (5 or 10 days for azithromycin and levofloxacin, respectively). The veterans (mean age, 56.8 years) received an exclusive outpatient dispensation of either amoxicillin (n = 979,380), azithromycin (n = 594,792), or levofloxacin (n = 201,798) at the Department of Veterans Affairs between September 1999 and April 2012. Azithromycin was dispensed mostly for 5 days, whereas amoxicillin and levofloxacin were dispensed mostly for at least 10 days. The results are consistent with a safety advisory issued by the FDA last year warning of the risks of possibly lethal arrhythmias when taking azithromycin or levofloxacin and a study uncovered that the risk of cardiovascular death was higher with azithromycin compared with amoxicillin or no antibiotic treatment. However, a Danish study showed that azithromycin was not associated with a greater risk of cardiovascular death in younger and middle-age adults in Denmark compared with penicillin.美国一项对退伍军人的回顾性研究表明，与阿莫西林相比，阿奇霉素和左氧氟沙星治疗期间（阿奇霉素和左氧氟沙星分别为5天和10天）死亡和严重心律失常风险升高。患者均为1999年9月至2012年4月期间在退伍军人事务部的独家门诊配药的退伍军人（平均年龄56.8岁），包括阿莫西林（ 979380例 ），阿奇霉素（ 594792例 ） ，或左氧氟沙星（ 201798例 ）。阿奇霉素配药多为5天，而阿莫西林和左氧氟沙星配药多为至少10天。该研究结果与美国食品药品管理局去年警告服用阿奇霉素或左氧氟沙星可能有致命性心律失常的风险，以及一项研究发现与阿莫西林或无抗生素治疗相比阿奇霉素具有较高的心血管病死亡的风险是一致的。然而，丹麦的一项研究表明，与青霉素相比阿奇霉素并未增加年轻和中年人心血管病死亡的风险。
