Synthroid overdose: signs, risks and what to do
Overdose of Synthroid (Levothyroxine) is uncommon at the standard 25mcg, 50mcg, 75mcg, 100mcg, 150mcg dose but can occur with accidental double dosing, intentional misuse or interactions. Knowing the signs and the right response is part of safe use, especially in households where Synthroid is shared or stored within reach of children.
Recognising overdose
Overdose typically presents as exaggerated versions of the medication's known side effects. With Levothyroxine, that can include severe hypotension, marked dizziness, confusion, persistent vomiting, prolonged visual disturbances, syncope, or, in extreme cases, cardiovascular instability. Symptom severity scales with the amount taken and with co-ingestion of alcohol or interacting drugs.
Immediate action
Suspected overdose is a medical emergency. Stop further dosing immediately and contact emergency services or your local poison control. Do not induce vomiting unless instructed by a healthcare provider. According to the prescribing information, no specific antidote exists for most Hormones and Birth Control agents — supportive care is the standard approach.
Frequently asked questions
How much Synthroid is too much? ▾
Any single dose above the maximum 25mcg, 50mcg, 75mcg, 100mcg, 150mcg prescribed strength, or any second dose taken inside the recommended interval, qualifies as a potential overdose risk and warrants caution. The exact threshold for symptoms varies between people.
Is Synthroid overdose deadly? ▾
Death from Synthroid overdose is rare with the active ingredient Levothyroxine alone. Risk is highest when combined with alcohol, with other interacting medications, or in people with underlying cardiovascular disease. Any suspected overdose should be evaluated urgently regardless.
More on Synthroid
- With alcoholSynthroid and alcohol — is it safe to drink?
- With foodShould Synthroid be taken with food?
- Side effectsSynthroid side effects: common, rare and warning signs
- Dosage guideSynthroid dosage guide: how much to take and when
- OnsetHow fast does Synthroid start working?
- DurationHow long does Synthroid last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.