Levothyroxine

DRUG INFORMATION

  ADULT
    - Levothyroxine Sodium Tablets Dosing Guidelines for Hypothyroidism in Adults*
      *Dosages greater than 200 mcg/day are seldom required.
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'dosage and administration', retrieved 2026-08-29
    - 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) ].
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'dosage and administration', retrieved 2026-08-29
    - 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.
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'dosage and administration', retrieved 2026-08-29

  CHILD
    - Levothyroxine sodium is indicated in patients from birth to less than 17 years of
      age: • As a replacement therapy in primary (thyroidal), secondary (pituitary), and
      tertiary (hypothalamic) congenital or acquired hypothyroidism. • As an adjunct to
      surgery and radioiodine therapy in the management of thyrotropin-dependent well-
      differentiated thyroid cancer.
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'pediatric use', retrieved 2026-08-29
    - • Administer once daily, preferably on an empty stomach, one-half to one hour
      before breakfast with a full glass of water. (2.1) • Administer at least 4 hours
      before or after drugs that are known to interfere with absorption. (2.1) •
      Evaluate the need for dose adjustments when regularly administering within one
      hour of certain foods that may affect absorption.
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'dosage and administration', retrieved 2026-08-29
    - Important Administration Instructions Administer levothyroxine sodium tablets as a
      single daily dose, on an empty stomach, one-half to one hour before breakfast with
      a full glass of water to avoid choking or gagging [see Adverse Reactions (6) ].
      Administer levothyroxine sodium tablets at least 4 hours before or after drugs
      known to interfere with levothyroxine sodium absorption [see Drug Interactions
      (7.1) ].
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'dosage and administration', retrieved 2026-08-29

  RENAL IMPAIRMENT
    - No kidney-impairment dose in this label. Not a statement that none is needed.
      Source: Read and found silent: the US FDA label for levothyroxine sodium
      (Levothyroxine sodium), retrieved 2026-08-29

  HEPATIC IMPAIRMENT
    - Nephrosis, severe hypoproteinemia, severe liver disease, acromegaly, androgens,
      and corticosteroids decrease TBG concentration.
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'warnings and cautions', retrieved 2026-08-29

  PREGNANCY
    - Risk Summary The clinical experience, including data from postmarketing studies,
      in pregnant women treated with oral levothyroxine to maintain euthyroid state have
      not reported increased rates of major birth defects, miscarriages, or other
      adverse maternal or fetal outcomes.
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'pregnancy', retrieved 2026-08-29
    - There are risks to the mother and fetus associated with untreated hypothyroidism
      in pregnancy.
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'pregnancy', retrieved 2026-08-29
    - Since TSH levels may increase during pregnancy, TSH should be monitored and
      levothyroxine sodium dosage adjusted during pregnancy (see Clinical
      Considerations) .
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'pregnancy', retrieved 2026-08-29

  BREASTFEEDING
    - Risk Summary Published studies report that levothyroxine is present in human milk
      following the administration of oral levothyroxine.
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'nursing mothers', retrieved 2026-08-29
    - No adverse effects on the breastfed infant have been reported and there is no
      information on the effects of levothyroxine on milk production.
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'nursing mothers', retrieved 2026-08-29
    - Adequate levothyroxine treatment during lactation may normalize milk production in
      hypothyroid lactating mothers with low milk supply.
      Source: US FDA label for levothyroxine sodium (Levothyroxine sodium), section
      'nursing mothers', retrieved 2026-08-29