Levothyroxine: Uses, Side Effects, and Drug Interactions

# Levothyroxine Overview Levothyroxine is a medicine used to treat an underactive thyroid gland, a condition called hypothyroidism. When your thyroid doesn't make enough thyroid hormone, your body's metabolism slows down and you may feel tired, gain weight, or feel cold. Levothyroxine is a man-made version of thyroid hormone that replaces what your body isn't making. It helps your body work at the right speed and feel normal again. This medication is usually taken as a pill by mouth and needs to be taken regularly to work properly. It's important to take levothyroxine safely by following your doctor's instructions carefully. Many other medicines can change how levothyroxine works in your body, so always tell your doctor and pharmacist about all the medications you're taking before starting levothyroxine. Your doctor will need to check your blood regularly to make sure you're taking the right dose—too much or too little can cause problems. Always take levothyroxine exactly as prescribed and don't change your dose without talking to your doctor first.