Eltroxin: what it is used for, dosage and side effects

What Eltroxin is and which active substance it contains

Eltroxin contains the active substance levothyroxine sodium. It is a synthetic equivalent of thyroxine, the hormone that the thyroid gland releases into the blood, and it is given as replacement for what the gland is not producing in sufficient amount.

In the European Medicines Agency data for the Maltese market the medicine is listed with the active substance anhydrous levothyroxine sodium and the route of administration: oral. It is a tablet, and it is taken long term in most cases.

Levothyroxine is on the Maltese list under several names, including Eltroxin and Thyrofix among others. That matters more here than with most medicines: products with the same substance are not automatically interchangeable, because small differences in how a tablet releases the substance can change the level in the blood. If a product is changed, a doctor will normally want a blood test afterwards to confirm that the dose is still right.

The strengths available and the excipients are in the patient information leaflet in your pack. The list of medicines authorised in Malta is kept by the Medicines Authority, and what an underactive thyroid actually is is explained in /health-guide/underactive-thyroid/.

What it is used for

The main use is an underactive thyroid, in other words a gland that does not produce enough hormone. That can arise from an autoimmune inflammation of the thyroid, after surgery on the gland, after treatment with radioactive iodine, from some medicines, or from a congenital condition.

It is also used after removal of the thyroid, where the medicine takes over the whole function of the gland, and in some cases to reduce the stimulation of thyroid tissue. Which of those situations applies to you changes what the treatment aims at, and therefore changes the dose.

The symptoms that lead people to a test are non-specific and are easy to attribute to something else: tiredness, feeling cold, weight gain, dry skin, hair thinning, constipation, low mood and, in women, changes in the cycle. None of them proves an underactive thyroid on its own; the diagnosis is made with a blood test.

This medicine is not a treatment for being overweight and must not be used to reduce weight in someone whose thyroid works normally. Used that way it does not treat anything and it exposes the heart and the bones to the effects of too much thyroid hormone. Weight treatment has its own route, described in /weight-loss-injections/.

How levothyroxine works and how treatment is monitored

The substance is absorbed from the gut and converted in the tissues into the more active form of the hormone. It acts on the metabolism of practically every organ, which is why both too little and too much have effects that are felt across the body.

The effect builds up gradually rather than appearing after the first tablet, and the same is true after a change of dose. That is why a doctor waits before testing again: measuring too early shows a level that has not yet settled and invites a change that is not needed.

Treatment is guided by a blood test, most often TSH, sometimes together with thyroid hormone levels. The test, not the patient's impression, is what decides the dose, and this is the main reason why a recent result is worth having to hand when asking about a repeat prescription.

The aim of treatment differs between situations: replacement after thyroid removal is not the same task as treating a mildly underactive gland, and the target range a doctor works to reflects that, as well as your age, heart health and, importantly, pregnancy.

Dosage and how the tablet is taken

The dose is individual and is set by a doctor, then adjusted against blood tests. In older people and in anyone with heart disease, treatment is usually begun cautiously and raised slowly, because the heart reacts to an increase in thyroid hormone. We do not quote strengths or step sizes on this page: they are in the leaflet for your pack and in your doctor's instruction.

Absorption is the part of this treatment that patients can influence, and it is easy to get wrong without knowing. The tablet is usually taken on an empty stomach with water, before breakfast, and separated in time from food as the leaflet directs. Taking it with breakfast reduces how much of it is absorbed, and doing so inconsistently makes blood results hard to interpret.

Some things are worth keeping well apart from the tablet in the day: calcium and iron supplements, antacids and products containing magnesium or aluminium, and some medicines used to lower cholesterol. Coffee and soya products also affect absorption. The leaflet for your pack gives the intervals to keep; the important part is to be consistent, so that the dose your doctor sets is the dose you actually absorb.

If you miss a tablet, follow the leaflet for your pack rather than doubling up on your own. Do not stop treatment because you feel well: feeling well on this medicine usually means the dose is right, not that the gland has recovered. Any change of dose belongs with a doctor, supported by a test.

Side effects and when to contact a doctor

At a correctly set dose, levothyroxine is replacing something the body should have, so the unwanted effects most often described are in fact the effects of too much of it. They include palpitations or a fast heartbeat, tremor, sweating, feeling too warm, restlessness, difficulty sleeping, headache, loose stools and unintended weight loss.

If those appear after a dose increase, or after a change of product, contact your doctor; it is a signal to test rather than to endure. Over a longer period, a dose that is too high is not neutral for the heart or for the bones, which is why this is not a medicine to adjust by feel.

Too low a dose brings back the symptoms of an underactive thyroid: tiredness, feeling cold, constipation, dry skin and low mood. That is also a reason to test rather than to add a tablet on your own initiative.

Chest pain, a markedly irregular heartbeat, severe breathlessness or fainting need urgent medical assessment; in an emergency in Malta, call 112. Allergic reactions to the tablet itself are rare and relate to excipients rather than to the hormone. How often each effect occurs is stated in the leaflet for your pack.

Interactions, other conditions and pregnancy

Beyond the products that reduce absorption, several medicines change how much thyroid hormone the body needs or how it is handled: some anticonvulsants, some medicines used in tuberculosis, oestrogen containing preparations and certain others. A doctor takes those into account, which is why the assessment needs a complete list of what you take, supplements and herbal products included.

Levothyroxine also affects other treatments. Anticoagulants taken by mouth can become stronger in their effect, and in diabetes the need for insulin or tablets can change as thyroid function is corrected. Neither of those is a reason not to treat the thyroid; they are reasons for a doctor to know and to monitor.

Untreated or poorly controlled adrenal insufficiency has to be addressed before thyroid hormone is started, and heart disease changes how cautiously treatment is begun. These are not points to be softened into a general caution: they change the plan.

Pregnancy deserves separate mention. The need for thyroid hormone usually rises during pregnancy, and an underactive thyroid that is not adequately treated carries risks for the pregnancy. If you are pregnant, think you may be, or are planning a pregnancy, tell your doctor promptly, because the dose and the testing schedule are likely to change and this is not something to manage through a questionnaire.

Prescription status, cover and the price at the pharmacy

Eltroxin is prescription only, so a pharmacy does not supply it without a prescription. The decision to prescribe, and the dose, belong to a doctor working from your test results. We do not sell medicines and we do not ship them; our service is a medical assessment and the issuing of a document.

Whether the medicine is covered by the public health service in Malta, and on what terms, is decided by the health authorities and not by us. Our service is private and is not covered by them, so the pharmacy price and our fee are two separate items. A pharmacy will tell you the current price of the pack.

The practical problem patients meet with this medicine is a pack running out during a trip or between appointments, since it is taken continuously and a break is not harmless. What to do in that situation is described in /blog/ran-out-of-medication-in-malta/, and the general picture of what we do and do not do is in /online-doctor/.

What we can do and what the fee covers

Our model is a medical questionnaire that a doctor reviews asynchronously, from your answers and any records you attach. There is no video call, no phone call and no live chat with a doctor. A questionnaire cannot replace a physical examination, so a first diagnosis of an underactive thyroid and the first setting of a dose need a doctor who examines you, orders tests and follows you up.

If the treatment is established and this is a continuation at an unchanged dose, you can ask for an assessment at /repeat-prescription/ for 24,90 €. Priority handling is available for an extra 9,90 €, which is not a promise of a deadline. A recent TSH result is the single most useful thing to attach, because without it a doctor is being asked to continue a treatment whose control cannot be checked. What a doctor looks for when renewing is described in /blog/repeat-prescription-without-a-visit/.

If the doctor issues a prescription, you receive the document by email as a PDF in the standard EU cross-border format set out in Directive 2012/52/EU; its recognition in another member state is governed by Directive 2011/24/EU. There is no code and the document is not entered in any Maltese state health record, so you go to the pharmacy with a printout or with the PDF on screen, together with photo identification. A pharmacy in Malta may dispense it; the decision rests with the pharmacist, who can refuse, for example where the pack is not available locally. What a pharmacy checks is explained in /blog/eu-prescription-maltese-pharmacy/.

The fee covers the doctor's assessment, not the issuing of a document. If the doctor declines on medical or legal grounds, we refund the fee. If we ask you for medical records, you have at least 7 days to reply. We then send a reminder and extend the deadline on request, and where the assessment still cannot be completed we close the request and refund the fee. The assessment is carried out by Damian Wojno, a doctor registered in Poland, licence no. 3211301, MEDINOW Sp. z o.o. He is not registered with the Medical Council of Malta, which keeps the register of doctors practising here; his licence to practise is Polish. Narcotic and psychotropic substances are excluded from cross-border prescriptions under Article 11(6) of Directive 2011/24/EU, and levothyroxine is not in that group.