Late amiodarone-induced thyrotoxicosis occurred in 7% of patients after amiodarone withdrawal and was significantly associated with prior amiodarone-induced hypothyroidism (100% vs. 24%, P=0.002) and longer therapy duration.
Cohort (n=71)
No
What is the incidence and what are the clinical characteristics of amiodarone-induced thyrotoxicosis occurring late after amiodarone withdrawal?
Amiodarone-induced thyrotoxicosis can develop months after drug withdrawal, particularly in patients with a history of amiodarone-induced hypothyroidism and long treatment duration, highlighting the need for continued thyroid monitoring.
BACKGROUND: Amiodarone-induced thyrotoxicosis (AIT) may develop long after amiodarone withdrawal. This study sought to determine the incidence and clinical characteristics of AIT after amiodarone withdrawal. METHODS AND RESULTS: The incidence and clinical characteristics of AIT were examined retrospectively in 71 patients (51 males, mean age 65±13 years) whose amiodarone therapy had been discontinued after at least 1 month of administration. Five (7%) patients developed AIT late after amiodarone withdrawal (11±3 months): 2 patients exhibited exacerbation of heart failure by atrial fibrillation, 2 developed dyspnea on exertion, and 1 patient was asymptomatic. The patients who developed AIT had a high incidence of amiodarone-induced hypothyroidism during amiodarone therapy (100 vs. 24%, P=0.002), had received amiodarone therapy for longer (76±86 months vs. 16±22 months, P<0.001), with a larger cumulative dose (271.1±268.5 g vs. 63.4±86.5 g, P<0.001) compared with those who did not. In all 5 patients, AIT resolved spontaneously within 5 months without the use of steroids. CONCLUSIONS: Occurrence of amiodarone-induced hypothyroidism during amiodarone therapy and long duration of therapy may be cautionary markers of late AIT.
Yagishita et al. (2013) conducted a cohort in Amiodarone-induced thyrotoxicosis (n=71). Amiodarone therapy and withdrawal vs. Patients without late AIT was evaluated on Incidence of late amiodarone-induced thyrotoxicosis (AIT) after amiodarone withdrawal. Late amiodarone-induced thyrotoxicosis occurred in 7% of patients after amiodarone withdrawal and was significantly associated with prior amiodarone-induced hypothyroidism (100% vs. 24%, P=0.002) and longer therapy duration.