What is Levothyroxine?
Levothyroxine is a prescription medication used to treat hypothyroidism (underactive thyroid). It is a synthetic version of the natural hormone thyroxine, which the thyroid gland should produce on its own. However, in people with hypothyroidism, the gland doesn’t produce enough thyroxine, meaning that a synthetic replacement is required.
Levothyroxine can also be used to treat hyperthyroidism (overactive thyroid) as a “block and replace” type of treatment, goiter (an enlarged thyroid gland) and can even be used for certain types of thyroid cancer.
The medicine can come in the form of tablets, capsules, or in some cases, an oral solution, and is safe to be used by all ages.
How do I take Levothyroxine?
It’s advised that you take Levothyroxine around 30-60 minutes before your first meal of the day. If you’re taking it in tablet or capsule form, it’s also recommended that you take the medication with a full glass of water (no caffeinated drinks until an hour after).
Food and caffeine can inhibit the effects of Levothyroxine, hence why guidance states that you should wait a while before eating, or drinking coffee and other caffeinated drinks.
It’s important to take the medicine at the same time each day in order to increase its effectiveness and to minimise variations in your blood levels. For levothyroxine to work properly, there must be a certain amount of it in your system at all times, so taking it at the same time each day not only helps you to remember it, but also helps to keep the thyroxine levels stable.
Levothyroxine should be available to you on repeat prescription due to it being a lifelong medication. Your doctor may monitor you periodically, especially if new health issues arise, but you shouldn’t need a new prescription unless your dosage has been changed.
What are the side effects of Levothyroxine?
As levothyroxine is a synthetic replication of a natural hormone, people don’t usually experience many side effects, but there are certain groups of people that may be more susceptible to them. If side effects do occur, they tend to mimic symptoms of hyperthyroidism (overactive thyroid), and it’s usually because the dose of levothyroxine is too high to begin with.
Some people may find that they experience hair loss during the first few months of treatment whilst their body gets used to the hormone, but this is almost always a temporary side effect. Whilst it can be unpleasant and distressing, it isn’t normally a cause for concern, but do raise the issue with your GP if it doesn’t improve within 3 months or so.
Generally, Levothyroxine tends to raise blood sugar levels, so if you already have diabetes, medication doses such as insulin may need to be increased to mitigate the adverse effects that levothyroxine could cause.
In some cases, and especially in patients with cardiovascular problems, using this medication may increase the risk of arrhythmia or other heart issues. It is normally recommended that people with heart disease and other similar conditions start with a much lower dose than what would be given to an otherwise healthy person.
Can I take Levothyroxine whilst pregnant?
If you’re already taking levothyroxine, absolutely! Your baby needs you to be healthy whilst you’re pregnant, but please visit your GP for advice as the dosage may need the be increased during this time. You will likely be monitored during the gestation period to make sure that your thyroxine levels are safe for you and your baby.
Which medications interact with Levothyroxine?
Despite the drug being a hormone replacement, there are still medications that can react with it:
- Antidepressants: some medicines commonly used to treat depression such as amitriptyline, sertraline and maprotiline can react with levothyroxine and increase your risk of arrhythmia (irregular heartbeat)
- Anticoagulants: medicines such as warfarin that are taken to thin the blood may interact with Levothyroxine, making your blood even thinner. Your doctor may need to adjust the dose of your anticoagulants if you’re starting on levothyroxine.
- Calcium and iron supplements: The synthetic hormone interacts with these supplements and may not be as effective. The same can be said for antacids.
- Combined contraceptive pills: these pills usually contain oestrogen which can lower the amount of levothyroxine in your body, so your doctor may increase your dose.
- Ketamine: using these drugs together may cause high blood pressure and tachycardia (fast heartbeat).
This list isn’t extensive, so please do disclose any other medications you’re taking to your GP or in the Doctor4U patient questionnaire, including herbal remedies and over the counter drugs.
My child has hypothyroidism; can they take levothyroxine?
As long as they’ve been diagnosed with the condition by a doctor, yes. Your child’s GP will work out what dosage they should be taking, and just as in adults, the levothyroxine should be taken with a full glass of water before breakfast each day.
How do I store levothyroxine?
It’s advised that you keep levothyroxine at room temperature, not exceeding 25 degrees celcius, in a dark and dry place. It might help to keep it by your bed or in the kitchen, somewhere that you’ll remember it easily each morning as part of your routine.
What are the risks with taking levothyroxine?
Despite levothyroxine just replacing a natural hormone, it can still pose a risk to some people, but they are often far outweighed by the need for thyroid medication.
Taking levothyroxine might increase your risk of developing osteoporosis, especially in women around the menopausal age. This condition can cause a low bone mineral density, making bones weaker and at risk of breaking easily. Whilst older people are at risk of this condition anyway, the use of levothyroxine can increase the likelihood of developing it.
There is a chance that the thyroid hormone medication can cause cardiovascular damage with long term use. If you have chest pains, or any symptoms of heart failure such as shortness of breath, swelling in the legs, and an irregular or fast heartbeat, seek emergency medical attention.
What happens if I miss a dose?
If you forget a dose one morning, take it as soon as you remember unless the next scheduled dose is due soon. In this case, skip the missed dose and resume treatment. Don’t take a double-dose to catch up.
If you forget more than one dose, you should contact your GP and look out for signs that you might be unwell.