Levothyroxine is a medicine used to treat hypothyroidism. If you have hypothyroidism, it means your thyroid gland produce too little thyroid hormone. With low thyroid hormone levels, your body cannot function properly, which may result in poor growth, lack of energy, excessive tiredness, weight gain, hair loss, increased sensitivity to cold, joint and muscle pain, heavy or irregular menstrual periods, and depression.

When taken correctly, levothyroxine provides thyroid hormone to you and restores the balance of thyroid hormone in your body. In addition, levothyroxine also can be used to treat goiter, which is an enlarged thyroid gland. It also treats certain types of thyroid cancer.

Important Warning
1. Levothyroxine, should not be used to treat weight loss or to treat obesity.
2. Levothyroxine may cause serious or life-threatening problems when taken higher than recommended doses. Therefore, never take more than the prescribed dose.
3. Levothyroxine is only available on prescription.
4. Please talk to your doctor before you start taking levothyroxine.

Before taking levothyroxine

  • Tell your doctor if you are allergic to this medicine or any other medicine. Also tell your doctor if you have any other types of allergies, such as to foods, preservatives or animals.
  • Tell your doctor if your thyroid is overactive (producing too much thyroid hormone- Thyroxine).
  • Tell your doctor if you have diabetes. This drug may affect your blood sugar levels. Therefore, check your blood sugar regularly as directed and share the results with your doctor.
  • Tell your doctor if you have a heart problem including heart disease or heart failure, or if you have high blood pressure.
  • Tell your doctor if you have adrenal insufficiency (a condition in which your adrenal glands do not produce enough of hormone cortisol). Please note, Cortisol is needed for important body functions. Your doctor may tell you not to take levothyroxine.
  • Levothyroxine doses need to be carefully monitored during pregnancy. If you’re planning to become pregnant or think you may be pregnant, it’s important to talk to your doctor to get the right care for you and your baby.
  • Tell your doctor if you are taking any other medicines. This includes any medicines which are available to buy without a prescription, as well as herbal medicines.
  • Tell your doctor if you have recently received radiation therapy.

How and when to take levothyroxine

How and when to take levothyroxine
  • Levothyroxine dosage is based on your age, weight, medical condition and laboratory test results. Therefore, please take levothyroxine exactly as directed by your doctor.
  • Levothyroxine comes as a tablet and a capsule to take by mouth. Your doctor will ask you to take one dose each day at least 30 minutes to 1 hour before having your breakfast and drink like tea or coffee. Because, food and drinks can both stop your body taking in levothyroxine properly.
  • Take the tablets with a full glass of water as they may get stuck in your throat or cause choking or gagging.
  • If levothyroxine has been prescribed for a child, the doctor will tell you what dose to give. The dose for children depends upon their weight, age and what they are being treated for.
  • For infants, children or adults who cannot swallow whole tablets, crush the tablet and mix in 1 to 2 teaspoons (5 to 10 milliliters) of water, and give using a spoon or dropper right away. Do not store it for later use. Consult your doctor for more information.
  • If you forget to take a dose, take it as soon as you remember, if it is still within one or two hours of your usual time. If it is longer than this, skip the forgotten dose. Do not take two doses together to make up for a missed dose. To help you remember, take the dose at the same time each day.

Please note, use levothyroxine regularly in order to get the most benefit. It may take several weeks before you notice a change in your symptoms. Furthermore, continue to take this medication even if you feel well. Do not stop taking levothyroxine without consulting with your doctor. Thyroid replacement treatment is usually taken for life.

Levothyroxine side effects

Like all medicines, Levothyroxine may cause side effects, although not everyone experiences them. Once you are on the right dose of levothyroxine, side effects should go away. However, tell your doctor if any of the following mentioned symptoms are severe or do not go away.

Common side effects

  • Headache
  • Vomiting
  • Diarrhea
  • Fever
  • Increased appetite
  • Weight loss
  • Hair Loss (usually temporary)
  • Muscle weakness
  • Shaking (usually of the hands)
  • Changes in menstrual periods
  • Mood changes
  • Insomnia (Trouble sleeping)
  • Sensitivity to heat

Please note, if these side effects are mild, they may go away within a few days or a couple of weeks. However, talk to your doctor if these side effects bother you or do not go away.

Furthermore, some people may have serious side effects when taking levothyroxine. If you experience either of the following serious side effects, call your doctor immediately.

Serious side effects

  • Chest pain
  • Shortness of breath
  • Discomfort in your upper body
  • Extreme Tiredness
  • Swelling of hands, feet, ankles, or lower legs
  • Unexpected weight gain
  • Very fast heart rate
  • Irregular heart rhythm
  • Itching
  • Rash
  • Tightness in the chest or throat
  • Stomach pain
  • Nausea

Please note, this is not a complete list of possible side effects. Therefore, if you experience any other effects not listed above, speak with your doctor or health care provider immediately.

Levothyroxine and pregnancy

Levothyroxine is safe to take in pregnancy.

It is important to take levothyroxine throughout your pregnancy. Having too low or too high levels of thyroid hormone in pregnancy may cause pregnancy loss or miscarriage. 

I am suffering from hashimoto hypothyroidism and also due to my history of three miscarriages my doctor advised me to take Levothyroxine regularly and without any gap. Therefore, during my recent pregnancy I took Levothyroxine strictly as prescribe by my doctor. Now I have healthy twin baby Girls. (:

In addition, I would also like to share with you that, you will need to have regular blood tests during pregnancy to make sure you are on the right dose of levothyroxine.

Levothyroxine and breastfeeding

Thyroid hormones play an important role in the production of breastmilk. So if you have a thyroid disorder it’s important that your thyroid hormone levels are well controlled after pregnancy, as well as before and during pregnancy.

Breastfeeding is safe while taking levothyroxine to treat an underactive thyroid (hypothyroidism). Levothyroxine pass into breast milk in extremely low amounts that are too small to affect your baby. If you are breastfeeding, it is important that you continue to take levothyroxine, as this is replacing what your body would normally be making.

Please note, if you notice that your baby is not feeding properly, or if you have any other concerns about your baby, talk to your healthcare provider or doctor immediately.

Blood Test to determine right dosage of Levothyroxine

To determine the right dosage, your doctor will do regular blood tests to check the levels of thyroid hormone in your body before and after starting levothyroxine.

At the start of treatment, your doctor may advise blood tests quite often but once your thyroid hormone levels are stable and your symptoms are under control, the frequency of blood tests may reduce.

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