DailyMed - LEVOTHYROXINE SODIUM tablet (2024)

2.1 Important Administration Instructions

Administer levothyroxine sodium tablets as a single daily dose, on an empty stomach, one-half to one hour before breakfast.

Administer levothyroxine sodium tablets at least 4 hours before or after drugs known to interfere with levothyroxine sodium tablets absorption [see Drug Interactions (7.1)].

Evaluate the need for dosage adjustments when regularly administering within one hour of certain foods that may affect levothyroxine sodium tablets absorption [see Dosage and Administration (2.2 and 2.3), Drug Interactions (7.9) and Clinical Pharmacology (12.3)].

Administer levothyroxine sodium tablets to pediatric patients who cannot swallow intact tablets by crushing the tablet, suspending the freshly crushed tablet in a small amount (5 to 10 mL) of water and immediately administering the suspension by spoon or dropper. Ensure the patient ingests the full amount of the suspension. Do not store the suspension. Do not administer in foods that decrease absorption of levothyroxine sodium tablets, such as soybean-based infant formula [see Drug Interactions (7.9)].

2.2 Important Considerations for Dosing

The dosage of levothyroxine sodium tablets for hypothyroidism or pituitary TSH suppression depends on a variety of factors including: the patient's age, body weight, cardiovascular status, concomitant medical conditions (including pregnancy), concomitant medications, co-administered food and the specific nature of the condition being treated [see Dosage and Administration (2.3), Warnings and Precautions (5), and Drug Interactions (7)]. Dosing must be individualized to account for these factors and dosage adjustments made based on periodic assessment of the patient's clinical response and laboratory parameters [see Dosage and Administration (2.4)].

For adult patients with primary hypothyroidism, titrate until the patient is clinically euthyroid and the serum TSH returns to normal [see Dosage and Administration (2.3)].

For secondary or tertiary hypothyroidism, serum TSH is not a reliable measure of levothyroxine sodium tablets dosage adequacy and should not be used to monitor therapy. Use the serum free-T4 level to titrate levothyroxine sodium tablets dosing until the patient is clinically euthyroid and the serum free-T4 level is restored to the upper half of the normal range [see Dosage and Administration (2.3)].

The peak therapeutic effect of a given dose of levothyroxine sodium tablets may not be attained for 4 to 6 weeks.

2.3 Recommended Dosage and Titration

Primary, Secondary, and Tertiary Hypothyroidism in Adults

The recommended starting daily dosage of levothyroxine sodium tablets in adults with primary, secondary, or tertiary hypothyroidism is based on age and comorbid cardiac conditions, as described in Table 1. For patients at risk of atrial fibrillation or patients with underlying cardiac disease, start with a lower dosage and titrate the dosage more slowly to avoid exacerbation of cardiac symptoms. Dosage titration is based on serum TSH or free-T4 [see Dosage and Administration (2.2)].

Table 1. Levothyroxine Sodium Tablets Dosing Guidelines for Hypothyroidism in Adults*

* Dosages greater than 200 mcg/day are seldom required. An inadequate response to daily dosages greater than 300 mcg/day is rare and may indicate poor compliance, malabsorption, drug interactions, or a combination of these factors. [see Dosage and Administration (2.1) and Drug Interactions (7)].

Patient Population
Starting Dosage
Dosage Titration Based on Serum TSH or Free-T4
Adults diagnosed with hypothyroidism
Full replacement dose is 1.6 mcg/kg/day. Some patients require a lower starting dose.
Titrate dosage by 12.5 to 25 mcg increments every 4 to 6 weeks, as needed until the patient is euthyroid.
Adults at risk for atrial fibrillation or with underlying cardiac disease
Lower starting dose (less than 1.6 mcg/kg/day)
Titrate dosage every 6 to 8 weeks, as needed until the patient is euthyroid.
Geriatric patients
Lower starting dose (less than 1.6 mcg/kg/day)

Primary, Secondary and Tertiary Hypothyroidism in Pediatric Patients

The recommended starting daily dosage of levothyroxine sodium tablets in pediatric patients with primary, secondary, or tertiary hypothyroidism is based on body weight and changes with age as described in Table 2. Titrate the dosage (every 2 weeks) as needed based on serum TSH or free-T4 until the patient is euthyroid [see Dosage and Administration (2.2)].

Table 2. Levothyroxine Sodium Tablets Dosing Guidelines for Hypothyroidism in Pediatric Patients

a Adjust dosage based on clinical response and laboratory parameters [see Dosage and Administration (2.4) and Use in Specific Populations (8.4)].

Starting Daily Dosage Per Kg Body Weighta
0 to 3 months
10 to 15 mcg/kg/day
3 to 6 months
8 to 10 mcg/kg/day
6 to 12 months
6 to 8 mcg/kg/day
1 to 5 years
5 to 6 mcg/kg/day
6 to 12 years
4 to 5 mcg/kg/day
Greater than 12 years but growth and puberty incomplete
2 to 3 mcg/kg/day
Growth and puberty complete
1.6 mcg/kg/day

Pediatric Patients from Birth to 3 Months of Age at Risk for Cardiac Failure.

Start at a lower starting dosage and increase the dosage every 4 to 6 weeks as needed based on clinical and laboratory response.

Pediatric Patients at Risk for Hyperactivity

To minimize the risk of hyperactivity, start at one-fourth the recommended full replacement dosage, and increase on a weekly basis by one-fourth the full recommended replacement dosage until the full recommended replacement dosage is reached.

Hypothyroidism in Pregnant Patients

For pregnant patients with pre-existing hypothyroidism, measure serum TSH and free-T4 as soon as pregnancy is confirmed and, at minimum, during each trimester of pregnancy. In pregnant patients with primary hypothyroidism, maintain serum TSH in the trimester-specific reference range.

The recommended daily dosage of levothyroxine sodium tablets in pregnant patients is described in Table 3.

Table 3. Levothyroxine Sodium Tablets Dosing guidelines for Hypothyroidism in Pregnant Patients
Patient Population
Starting Dosage
Dose Adjustment and Titration
Pre-existing primary hypothyroidism with serum TSH above normal trimester- specific range
Pre-pregnancy dosage may increase during pregnancy
Increase levothyroxine sodium tablet dosage by 12.5 to 25 mcg per day. Monitor TSH every 4 weeks until a stable dose is reached and serum TSH is within normal trimester-specific range. Reduce levothyroxine sodium tablet dosage to pre-pregnancy levels immediately after delivery. Monitor serum TSH 4 to 8 weeks postpartum.
New onset hypothyroidism (TSH ≥ 10 IU per liter)
1.6 mcg/kg/day
Monitor serum TSH every 4 weeks and adjust levothyroxine sodium tablet dosage until serum TSH is within normal trimester-specific range.
New onset hypothyroidism (TSH < 10 IU per liter)
1.0 mcg/kg/day

TSH Suppression in Well-differentiated Thyroid Cancer in Adult and Pediatric Patients

The levothyroxine sodium tablets dosage is based on the target level of TSH suppression for the stage and clinical status of thyroid cancer.

2.4 Monitoring TSH and/or Thyroxine (T4) Levels

Assess the adequacy of therapy by periodic assessment of laboratory tests and clinical evaluation. Persistent clinical and laboratory evidence of hypothyroidism despite an apparent adequate replacement dose of levothyroxine sodium tablets may be evidence of inadequate absorption, poor compliance, drug interactions, or a combination of these factors.


In adult patients with primary hypothyroidism, monitor serum TSH levels after an interval of 6 to 8 weeks after any change in dosage. In patients on a stable and appropriate replacement dosage, evaluate clinical and biochemical response every 6 to 12 months and whenever there is a change in the patient's clinical status.

Pediatric Patients

In patients with hypothyroidism, assess the adequacy of replacement therapy by measuring both serum TSH and total or free-T4. Monitor TSH and total or free-T4 in pediatric patients as follows: 2 and 4 weeks after the initiation of treatment, 2 weeks after any change in dosage, and then every 3 to 12 months thereafter following dosage stabilization until growth is completed. Poor compliance or abnormal values may necessitate more frequent monitoring. Perform routine clinical examination, including assessment of development, mental and physical growth, and bone maturation, at regular intervals.

The general aim of therapy is to normalize the serum TSH level. TSH may not normalize in some patients due to in utero hypothyroidism causing a resetting of pituitary-thyroid feedback. Failure of the serum T4 to increase into the upper half of the normal range within 2 weeks of initiation of levothyroxine sodium tablets therapy and/or of the serum TSH to decrease below 20 IU per liter within 4 weeks may indicate the patient is not receiving adequate therapy. Assess compliance, dose of medication administered, and method of administration prior to increasing the dose of levothyroxine sodium tablets [see Warnings and Precautions (5.1) and Use in Specific Populations (8.4)].

Secondary and Tertiary Hypothyroidism

Monitor serum free-T4 levels and maintain in the upper half of the normal range in these patients.

DailyMed - LEVOTHYROXINE SODIUM tablet (2024)



Levothyroxine sodium tablets are a L-thyroxine (T4) indicated in adult and pediatric patients, including neonates, for: Hypothyroidism: As replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism.

Is it better to take levothyroxine at night or in the morning? ›

Conclusions Levothyroxine taken at bedtime significantly improved thyroid hormone levels. Quality-of-life variables and plasma lipid levels showed no significant changes with bedtime vs morning intake. Clinicians should consider prescribing levothyroxine intake at bedtime.

What are levothyroxine sodium tablets used for? ›

Levothyroxine is a medicine used to treat an underactive thyroid gland (hypothyroidism). The thyroid gland makes thyroid hormones which help to control energy levels and growth. Levothyroxine is taken to replace the missing thyroid hormone thyroxine. Levothyroxine is only available on prescription.

How much levothyroxine sodium should I take? ›

The dose is usually 1.7 microgram (mcg) per kilogram (kg) of body weight per day but may be less in older adults. Children older than 12 years of age (growth and puberty incomplete)—Dose is based on body weight and must be determined by your doctor. The dose is usually 2 to 3 mcg per kg of body weight per day.

What vitamins should not be taken with thyroid medication? ›

Don't take calcium supplements or antacids at the same time you take thyroid hormone replacement. Take any products containing calcium at least four hours before or after taking thyroid hormone replacement.

What is the downside to taking levothyroxine? ›

It's one of the most common medications prescribed in the U.S. Common levothyroxine side effects include heat intolerance, a fast heart rate, and diarrhea. Weight loss and hair changes are also possible.

What foods should I avoid with levothyroxine? ›

Levothyroxine Food

In addition, absorption of levothyroxine may be decreased and/or delayed by foods such as soybean flour, cotton seed meal, walnuts, dietary fiber, calcium, calcium fortified juices and grapefruit or grapefruit juice. These foods should be avoided within several hours of dosing if possible.

Which fruit is not good for the thyroid? ›

Excessive consumption of these foods can result in thyroid gland inflammation and worsen the condition. These include: Some fruits, such as strawberry, peaches, Starchy food, such as sweet potato and cassava.

Can I drink coffee 30 minutes after taking levothyroxine? ›

Coffee may reduce levothyroxine absorption, so it may be a good idea to wait at least 30–60 minutes after taking the medication before enjoying your first sip of java.

Do you gain weight with levothyroxine? ›

Levothyroxine does not directly cause weight gain, though it may increase your appetite. Still, it may be more likely to cause weight loss as it restores your thyroid function and metabolism.

Why do you have to drink a full glass of water with levothyroxine? ›

Take the tablets with a full glass of water as they may get stuck in your throat or cause choking or gagging. If you are giving levothyroxine to an infant, child, or adult who cannot swallow the tablet, crush and mix it in 1 to 2 teaspoons (5 to 10 mL) of water.

What happens to your body when you start taking levothyroxine? ›

Levothyroxine is generally well-tolerated, but it still has the potential to cause side effects. Heat intolerance, sweating, and diarrhea have been reported, especially when you're first starting the medication or changing doses.

How can you tell if your thyroid medication is working? ›

You should start to feel better a few days after you begin taking medicine. But it may take a few months for your thyroid hormone levels to get back to normal. If your levels get better, but you still have symptoms like fatigue and weight gain, your doctor may need to adjust your treatment.

Can I take vitamin D with levothyroxine? ›

Interactions between your drugs

No interactions were found between levothyroxine and Vitamin D3. However, this does not necessarily mean no interactions exist. Always consult your healthcare provider.

What not to mix with thyroid medication? ›

The medicines and supplements that should not be taken within 4 hours of taking levothyroxine include:
  • Calcium supplements (including those found in multivitamins)
  • Iron supplements (including those found in multivitamins)
  • Antacids.
  • Sucralfate.
  • Phosphate binders (calcium carbonate, ferrous sulfate, sevelamer, lanthanum)
Sep 26, 2023

What drugs interact badly with levothyroxine? ›

Some of the most significant medication and supplement interactions occur with antacids, bile acid sequestrants, ion exchange resins, iron supplements, and calcium. Levothyroxine should be taken 4 hours apart from any of these products.

Why can't you take thyroid medicine at night? ›

For most people, it doesn't really matter if you take your thyroid medications in the morning or at night before bedtime. It's more about what suits your lifestyle best.

Does timing of levothyroxine matter? ›

The absorption of levothyroxine in the gut is decreased when taking the hormone at the same time as calcium, iron and some foods and other drugs. Because of this, patients are usually instructed to take levothyroxine on an empty stomach 30-60 minutes before food intake to avoid erratic absorption of the hormone.

Can I go back to bed after taking levothyroxine? ›

Unless your doctor gives you different directions, you can lie down after taking it. The prescribing information for levothyroxine advises you to take one pill daily on an empty stomach 30 minutes to 1 hour before breakfast. Levothyroxine is an oral medication used to treat hypothyroidism.


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