Division of Internal Medicine, McGill University Health Center, Montréal, Que.
CMAJ. 2011 Sep 6;183(12):E817-23. doi: 10.1503/cmaj.101800. Epub 2011 Jul 11.
Amiodarone is associated with dysfunction of the thyroid. Concerns have arisen regarding the potential for adverse effects with generic formulations of amiodarone. We evaluated and compared the risk of thyroid dysfunction between patients using brand-name versus generic formulations of amiodarone and identified risk factors for thyroid dysfunction.
We conducted a retrospective cohort study of patients with atrial fibrillation aged 66 years and older. We used administrative databases that linked information on demographics and clinical characteristics, claims for prescription drugs and discharges from hospital. We estimated thyroid dysfunction using person-year incidence.
Of the 60,220 patients in the cohort, 2804 (4.7%) used the brand-name formulation of amiodarone and 6278 (10.4%) used the generic formulation. Baseline characteristics between these two groups were comparable. The median maintenance dose of amiodarone was 200 mg/d for both groups. The total incidence rate for thyroid dysfunction was 14.1 per 100 person-years for both formulations. The mean time to clinical dysfunction of the thyroid was 4.32 years for the brand-name formulation and 4.09 years for the generic formulation. In a multivariate analysis, there was no significant difference in the incidence rates of thyroid dysfunction between the generic and brand formulations (hazard ratio 0.97, 95% confidence interval 0.87-1.08). Factors associated with an increased risk of thyroid dysfunction were being a woman, increasing age and having chronic obstructive pulmonary disease.
In this population-based study, we saw no difference between brand-name and generic formulations of amiodarone in terms of incidence of thyroid dysfunction.
胺碘酮可引起甲状腺功能障碍。人们对胺碘酮的通用制剂可能产生不良反应表示担忧。我们评估并比较了使用胺碘酮品牌制剂和通用制剂的患者发生甲状腺功能障碍的风险，并确定了甲状腺功能障碍的危险因素。
我们对年龄在 66 岁及以上的心房颤动患者进行了回顾性队列研究。我们使用了行政数据库，该数据库将人口统计学和临床特征、处方药和住院记录相关信息联系起来。我们使用人年发病率来估计甲状腺功能障碍。
在该队列的 60220 名患者中，有 2804 名（4.7%）使用了胺碘酮的品牌制剂，6278 名（10.4%）使用了通用制剂。这两组的基线特征相当。两种制剂的胺碘酮维持剂量中位数均为 200mg/d。甲状腺功能障碍的总发生率为两种制剂均为 14.1/100 人年。品牌制剂和通用制剂的甲状腺功能障碍的平均临床发病时间分别为 4.32 年和 4.09 年。多变量分析显示，两种制剂的甲状腺功能障碍发生率无显著差异（风险比 0.97，95%置信区间 0.87-1.08）。与甲状腺功能障碍风险增加相关的因素包括女性、年龄增加和慢性阻塞性肺疾病。
在这项基于人群的研究中，我们发现品牌制剂和通用制剂的胺碘酮在甲状腺功能障碍的发生率方面没有差异。
