Levothyroxine Poisoning – Symptoms and Clinical Outcome

Levothyroxine (LT), T4, poisoning is rarely associated with a severe outcome. However, cases with significant complications have been reported. The aim of this study was to identify factors associated with symptoms of poisoning including late‐onset symptoms. All enquiries to the Danish Poison Information Centre (DPIC) concerning LT poisoning between March 2007 and September 2012 were reviewed and the following parameters were recorded: age, dose, time from ingestion, multiple drug intake and symptoms. To evaluate the frequency of late‐onset symptoms, a subgroup of patients without initial symptoms were contacted. A total of 181 patients were registered (112 children). Ingested LT dose ranged from 10 to 9000 mcg (median 275 mcg). A total of 29 of 181 (16%) patients were symptomatic at the time of enquiry, and there was no difference in ingested LT dose between asymptomatic and symptomatic patients, neither in children nor in adults (age 16–92 years) (p