Hi,
Based on the history you seem to have mistaken an extra dose of Synthroid. As long as you do not have symptoms of overdose it is not an issue.
An occasional extra pill will make little difference more so if taken on full stomach which will hinder its absorption for the gut. Take your next tablet as usual.
However, if you have any of these symptoms go to the emergency room like rapid or irregular heartbeats, chest pain, leg cramps, headaches,
nervousness, irritability,
sleeplessness, tremors, vomiting, diarrhea,
excessive sweating, heat intolerance, or a fever.
In that case, you may be given activated charcoal and cholestyramine(to prevent further absorption of synthroid from the gut),
propranolol,
dexamethasone, and supporting measures, with close monitoring.
Hope I have answered your query. Let me know if I can assist you further.
Take care
Regards,
Dr. Mohammed Taher Ali, General & Family Physician