What should I do right now if I missed my Synthroid (levothyroxine) dose?
If you forgot to take Synthroid this morning, take the general approach below:
- If you only missed one dose and you remember later the same day, take your usual dose when you remember.
- If you do not remember until the next day, do not double up to make up for the missed dose—take your next scheduled dose instead.
Doubling up can raise the chance of side effects from too much thyroid hormone (like palpitations, shakiness, headache, or feeling unusually anxious).
Should I take two doses if I missed one morning dose?
Usually, no. For a missed morning dose, the typical guidance is to continue your regular schedule and skip the missed dose rather than taking two doses the next day.
What if I missed it for more than one day?
If you missed multiple days, the best next step is to follow your prescriber’s instructions or contact your pharmacy/clinician for personalized advice. Several factors matter, including:
- how long you’ve missed doses
- the reason you take Synthroid (hypothyroidism vs. thyroid cancer suppression)
- your most recent thyroid lab results (TSH/free T4)
What symptoms should make me call my doctor?
Seek medical advice promptly if you develop signs of taking too much thyroid hormone (or if you’re worried you may have overdosed), such as:
- rapid or irregular heartbeat, chest pain
- severe anxiety, tremor, shortness of breath
- severe headache or dizziness
- feeling very unwell
If you feel fine, one missed dose typically isn’t an emergency.
How can I prevent this from happening again?
Common practical fixes include:
- taking it right when you wake up and pairing it with a daily habit (like brushing teeth)
- using a pill organizer or phone reminder
- keeping it somewhere you’ll reliably see it in the morning
One key detail: how Synthroid is taken affects absorption
When you take it, keep your routine consistent because food and some supplements can reduce absorption. Follow the instructions you were given (often taking it on an empty stomach and waiting before eating, and spacing it from iron or calcium supplements).
If you tell me (1) what time it’s currently, (2) whether you remember any dose since morning, and (3) when you normally take Synthroid, I can suggest the safest way to handle today’s doses based on the usual missed-dose approach.