Taking L-Thyroxine for Hypothyroidism – All You Really Need To Know

L-Thyroxine is a drug which is commonly prescribed for those who have been diagnosed with hypothyroidism, a medical condition in which the thyroid functions at a slow rate and fails to produce adequate quantities of hormones.

The treatment is prescribed by a specialized physician (endocrinologist), who will decide on the dosage and offer information on potential side-effects, or interactions with other medication.

The active ingredient in this drug is levothyroxine, which has similar effects with the actual thyroid hormone. This drug is recommended either to replace the thyroid hormone that is missing or to support the thyroid gland, upon having difficulties in producing enough of the respective hormone. Apart from hypothyroidism, as you will see, L-Thyroxine might be prescribed as a treatment for the benign goiter. (R)

For who is L-Thyroxine recommended?

In the situation that one does not have enough thyroid hormones within the body, as a result of hypothyroidism, the treating physician might prescribe replacement therapy in the form of L-Thyroxine.

This treatment is also recommended in the situation the thyroid functions normally, with a removed goiter being part of the medical history. In this case, the purpose of the treatment is to prevent the reappearance of the goiter and, thus, the enlargement of the actual gland.

L-Thyroxine can be used for the actual treatment of the benign goiter and also as adjunctive therapy for hyperthyroidism (under treatment). In the situation that one has had surgery for the removal of a malignant tumor at the level of the thyroid gland, L-Thyroxine might be used to suppress the recurrent tumor growth (post-surgical treatment). Last, but not least, L-Thyroxine is employed in the thyroid suppression test, serving the purpose of checking if the thyroid gland functions within normal limits or not.

Dosage and frequency

The physician will decide on both the dosage and frequency of your L-Thyroxine treatment. The drug is available in the form of tablets, with different content of active ingredient. The content of levothyroxine might be of 25, 50, 75, 100, 125, 150, 175 or 200 micrograms. In general, patients are advised to take one tablet per day.

If a person suffers from hypothyroidism, the doctor might prescribe one tablet of L-Thyroxine per day, containing between 25 and 50 micrograms of the active ingredients. Provided the thyroid function does not improve, the dosage might be increased to 100 or even 200 micrograms per day (single dose).

The recommended dosage for goiter prevention (post-surgery) or benign goiter treatment varies between 75 and 200 grams of L-Thyroxine. In the case of post-surgical prevention of malignant tumor growth, the dosage advised starts at 150 and goes as far as 300 micrograms, in the form of a single tablet. For the thyroid suppression test, one should take 200 micrograms of L-Thyroxine for a period of two weeks.

You should always respect the recommendations made by the doctor with regard to this treatment. Keep in mind that each patient has different needs in terms of quantity, dose, and mode of administration. The quantities presented above are for informational purposes only and they do not substitute medical advice. (R)

Things to consider when following the treatment with L-Thyroxine

It is not advisable to take the L-Thyroxine treatment with food, as this can have a negative impact on your diet and prevent the adequate absorption of the medication. For the best results, you should take the medication in the morning, prior to eating (with at least half an hour before serving breakfast). In this way, the hormone will be absorbed to its full extent and serve the intended purpose.

To ensure this adequate absorption, you should take the tablet with a tall glass of water. In the situation that you have forgotten to take your medication, skip the respective dose and follow your treatment as usual. Refrain from taking two tablets at once, as you might suffer from a dangerous overdose. If you have questions or uncertainties about your treatment, do not hesitate to schedule an appointment with your treating physician.

Duration of the treatment varies

In deciding on the duration of the treatment with L-Thyroxine, the doctor will consider the actual condition you are suffering from. If you have been diagnosed with hypothyroidism, the medication should be taken all of your life. The same goes for the prevention of tumoral recurrence in case of thyroid surgery (for malignant tumors).

If you have been diagnosed with a benign goiter, the treatment might last as little as several months or be necessary throughout the entire life. You might expect the same thing for the prevention of new goiter growth. The standard period, however, for the treatment of a benign goiter varies between six months and two years.

When L-Thyroxine is prescribed as adjunctive therapy for hyperthyroidism, this should be taken until the anti-thyroid medication works its effect and brings back the thyroid gland to its normal functioning. This treatment should never be used, as you will read below, in the case of untreated hyperthyroidism.

Interactions with other medication

If you are taking L-Thyroxine at the same time with other drugs, it is worth knowing that there is a risk of drug interactions. It might be for the best to talk to your doctor about potential interactions. The pharmacist can also be of use in this department. Remember that L-Thyroxine can influence the effectiveness of various other drugs and vice versa.

For example, L-Thyroxine can interact with the medication prescribed to lower blood sugar in case of diabetes, such as insulin, glibenclamide, glimepiride or metformin).  The thyroid medication can accentuate the effect of anticoagulant drugs, such as coumarin derivatives (warfarin, dicoumarol, phenprocoumon).

Ion-exchange resins, such as sevelamer, colestipol, colestyramine, calcium and sodium salts of polysterene sulfonic acid, should be taken 4 to 5 hours after L-Thyroxine. The same goes for bile acid sequestrants, such as colesevelam.

The medication prescribed for gastric problems, such as antacids or other medication containing alcohol, calcium carbonate or iron should be taken 2 hours after L-Thyroxine.

Certain drugs, such as glucocorticoids (and especially cortisone) and beta blockers (propranolol in particular) might cause L-Thyroxine to be less effective. Contrast agents that include iodine or other similar substances can affect the functioning of the thyroid gland, when taken in combination with L-Thyroxine (over or underactive).

Medication prescribed to inhibit thyrosine kinase can cause L-thyroxine to be less effective. The same goes for other drugs in high doses, such as furosemide or salicylates.

If you are talking hormonal treatments based on estrogen, as part of hormone replacement therapy, you might need to increase your L-Thyroxine dose. Chloroquine and different drugs recommended for psychiatric/neurologic conditions, such as barbiturates, carbamazepine or rifampicin might reduce the effect of this thyroid drug. The same goes for any medication falling under the protease inhibitors category (lopinavir, ritonavir). In rare cases, the drug orlistat can actually cause hypothyroidism or affect the ability to keep this condition under control. (R)

What are the potential side-effects of L-Thyroxine?

In general, this thyroid treatment is well-tolerated and it does not lead to any side-effects.

In the situation that side-effects occur, these can include: inability to sleep, heart palpitations, headaches, a state of nervousness or restlessness, hypersensitivity, tremors, arrhythmia, increased intracranial pressure, vomiting and diarrhea, weight loss, hot flashes, rash on the skin, profuse sweating, fever, muscle weakness and cramps.

If you are experiencing any of the above-mentioned side-effects, it is advisable to contact your doctor as soon as it is possible. You might need to change or adjust your treatment.

Is L-Thyroxine contraindicated in some cases?

Like with any other medication, there are contraindications to take into consideration. For example, if you have a known sensitivity to the active substance (levothyroxine), then the treatment is not recommended. The same goes for untreated hyperthyroidism or the weakness of the adrenal cortex. If you have recently suffered a heart attack or were diagnosed with the acute inflammation of the heart muscle/walls, you should not take L-Thyroxine. (R)

Hypothyroidism, the most common thyroid disorder in the world

L-Thyroxine is primarily recommended for the treatment of hypothyroidism, which is the most common thyroid disorder in the world. The condition affects mostly middle-aged women, especially those who are over the age of 50. It slows down not only the functioning of the thyroid but of the entire body, leading to a general state of fatigue, cold intolerance and dry skin (among other physiological and psychological changes).

A sub-type of hypothyroidism is an autoimmune condition, which is known as Hashimoto’s thyroiditis. The thyroid gland practically destroys itself, with the condition affecting up to ten million people only in the United States. The condition cannot be prevented but it can be kept under control with specific treatment. As mentioned, the treatment for hypothyroidism must be taken throughout the entire life but it does work to improve the thyroid function and, subsequently, the overall quality of life. (R)

CareClinic’s health app, ideal for recording your thyroid treatment plan

CareClinic is a free health app, available on both iOS and Android, which can be used to record your thyroid treatment plan. You can add L-Thyroxine as a primary drug, using the application to record its dosage and frequency, as well as potential side-effects and drug interactions.

The application can also be used to create medication reminders. Thanks to CareClinic, you will never forget to take your treatment again (superior medication adherence). You will be sent push notifications or text alerts to take your treatment and there is also a snooze feature, which will keep on sending reminders in cased of missed doses.

CareClinic serves as an excellent health app, helping you stay in control of your thyroid treatment. It has received approval from expert physicians, endocrinologists included. The app comes with a health diary, in which you can record your thyroid disorder symptoms, health measurements and other useful health-related data.

Thanks to this health app, you can record not only your treatment with L-Thyroxine but also any other medication you are taking. The application will highlight potential interactions, as well as synergistic effects. You can record the progress you have made on this treatment and even export monthly reports, which can be then shared with the doctor.

The symptom tracker is also useful, as the symptoms of hypothyroidism can be unspecific. You can record how you are feeling every day and, at the end of the month, use the generated report to get a clear perspective about your general health. Apart from symptoms and treatment, you can record aspects related to mental health, sleep, diet and physical activity.

Never forget to take your L-thyroxine tablets, sign up for CareClinic by clicking here.

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Alexandra V.
Alexandra V.
Alexandra V. holds a degree in Physiotherapy from the University of Medicine and Pharmacy Carol Davila. She holds an additional degree in Journalism and writes in English and German. She is passionate about preventative health care and an undergrad in Medicine.
Alexandra V.