Friday, 20th September, 2019

What is Levothyroxine?

What is levothyroxine?

Levothyroxine is a medicine to treat an underactive thyroid gland, also known as hypothyroidism. The thyroid gland makes thyroid hormones which control energy levels and growth.

What does levothyroxine do?

Levothyroxine replaces the thyroid hormone that your body would have naturally produced if the thyroid gland was working as expected.

How do I take levothyroxine?

Take levothyroxine once a day in the morning. It’s important to have it about 30 minutes before eating or drinking anything other than water to make sure you absorb the right amount. Food and caffeinated drinks (like tea or coffee) at the same time as your dose will stop your body taking in levothyroxine properly.

Getting the right dose of levothyroxine

Levothyroxine is most commonly available in tablets of 25, 50, and 100 micrograms. There are also tablets containing 12.5 and 75 micrograms. It’s normal to take a combination of these tablets in order to get the right dose for you. Liquid forms are available too.

You’ll need to have blood tests to check if the amount of levothyroxine in your body is correct and your GP will increase or decrease your daily dose depending on these test results. Blood tests tend to be quite regular to begin with and eventually will be about once or twice a year. If you take medicines that affect levothyroxine, are pregnant, or experience side effects, then you may need more regular blood tests.

Levothyroxine and pregnancy

Levothyroxine is generally safe to take in pregnancy and while breastfeeding.

In fact, it's important to carry on taking levothyroxine throughout your pregnancy. Having too low or too high levels of thyroid hormone in pregnancy can cause problems for you and your baby. You'll need to have regular blood tests during pregnancy to make sure you're on the right dose of levothyroxine for you and your baby. Most women need to take a higher dose of levothyroxine than usual while they're pregnant.

Common side effects

Side effects normally happen if the dose is too high. Once the dose is right for you, any side effects should disappear because the levothyroxine you are taking is just replacing what your own body would have produced if your thyroid gland was working as expected.

Common side effects are the same as the symptoms of an overactive thyroid. Talk to your doctor or pharmacist if these side effects bother you or don't go away:

  • feeling sick
  • being sick (vomiting) or diarrhoea
  • headaches
  • feeling restless or excitable, or having problems sleeping
  • flushing or sweating
  • muscle cramps
  • shaking, usually of the hands

Other side effects

It happens rarely, but some people may have serious side effects when taking levothyroxine.

Call a doctor straight away if you get:

  • chest pain
  • fast or irregular heartbeats, or palpitations

Medicines that can stop you absorbing levothyroxine

Some medicines shouldn't be taken at the same time of day as levothyroxine as they can reduce the amount of levothyroxine your body takes in, including:

  • antacids
  • calcium salts
  • iron salts
  • orlistat, a medicine used for weight loss
  • sucralfate, a medicine used to treat stomach ulcers
  • some cholesterol-lowering medicines such as colestyramine, colestipol or colesevelem (not statins)

Want to learn more? Watch our two-minute video with Alistair Murray, Chief Pharmacist at Echo, sharing the keys facts about levothyroxine. 

Recommended reading:

If you’d like more information on levothyroxine, we always recommend checking out the NHS website. For more information on underactive thyroid, including symptoms and causes, please check out the NHS website. 

Lastly, if you’d like to learn more about thyroid conditions, we recommend checking out the British Thyroid Foundation.

As always, the NHS has a wealth of information on making sure you have a balanced diet. Check out this link for quick and healthy recipes, meal planning and much more.

Who is Alistair?

Alistair Murray - MRPharmS

Chief Pharmacist- Echo Pharmacy

Alistair is a seasoned healthcare professional with over 20 years' experience working with community and digital pharmacy, third-level education and the NHS. He completed his pharmacy training at Boots and spent 15 years as a pharmacist working in community pharmacies and GP surgeries before joining the founding team of Echo in 2015. He is an honorary lecturer at UCL and the University of Nottingham, the latter where he received his masters in pharmacy.

Alistair is passionate about adherence and making sure that people are making informed choices when it comes to their health.