Levothyroxine
ThyroidAlso known as Synthroid, Levoxyl, Euthyrox
Your thyroid gland sets the pace for your whole body — energy, temperature, weight, mood. When it's underactive, levothyroxine tops up the missing hormone so everything runs at normal speed again. It can take several weeks to feel the difference, so be patient and don't change your dose on your own.
How to take it
When
First thing in the morning, on an empty stomach, 30 to 60 minutes before breakfast. Water only.
Food
Food, coffee, and milk can block absorption — that's why the empty stomach matters.
Avoid
Calcium, iron, and antacids within 4 hours of your dose. They bind to the medicine and stop it working.
How long
Usually lifelong. Your doctor will fine-tune the dose with blood tests.
Missed a dose?
Take it when you remember that day. If you don't remember until the next day, ask your doctor — some people are told to take two tablets that day, but don't do this without asking first.
Common side effects
- Most side effects mean the dose is a bit too high, not that the medicine is wrong for you
- Racing heart or palpitations
- Feeling hot, sweaty, or shaky
- Trouble sleeping, unintended weight loss
Call a doctor if
- Chest pain or a very fast, irregular heartbeat
- Severe shortness of breath
- Tell your doctor about ongoing shakiness, sweating, or sleep problems — your dose may need adjusting