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Levothyroxine Dosage

Medically reviewed by Drugs.com. Last updated on Sep 14, 2023.

Applies to the following strengths: 25 mcg (0.025 mg); 50 mcg (0.05 mg); 75 mcg (0.075 mg); 100 mcg (0.1 mg); 125 mcg (0.125 mg); 150 mcg (0.15 mg); 200 mcg (0.2 mg); 300 mcg (0.3 mg); 500 mcg (0.5 mg); 88 mcg (0.088 mg); 112 mcg (0.112 mg); 175 mcg (0.175 mg); 137 mcg (0.137 mg); 13 mcg (0.013 mg); 100 mcg (0.1 mg)/mL; 150 mcg (0.15 mg)/5 mL; 100 mcg (0.1 mg)/5 mL; 20 mcg (0.02 mg)/mL; 40 mcg (0.04 mg)/mL; 37.5 mcg (0.0375 mg); 44 mcg (0.044 mg); 62.5 mcg (0.0625 mg); 13 mcg (0.013 mg)/mL; 25 mcg (0.025 mg)/mL; 37.5 mcg (0.0375 mg)/mL; 44 mcg (0.044mg)/mL; 50 mcg (0.05 mg)/mL; 62.5 mcg (0.0625 mg)/mL; 75 mcg (0.075 mg)/mL; 88 mcg (0.088 mg)/mL; 112 mcg (0.112 mg)/mL; 125 mcg (0.125 mg)/mL; 137 mcg (0.137 mg)/mL; 150 mcg (0.15 mg)/mL; 175 mcg (0.175 mg)/mL; 200 mcg (0.2 mg)/mL

Usual Adult Dose for:

Usual Geriatric Dose for:

Usual Pediatric Dose for:

Additional dosage information:

Usual Adult Dose for Hypothyroidism

Dosing should be individualized with consideration given to age, cardiovascular status, concomitant medical conditions (including pregnancy), and specific nature of condition; follow clinical response and laboratory parameters closely as dose is adjusted:

INITIAL DOSES:
Primary Hypothyroidism: For otherwise healthy individuals in whom growth and puberty are complete:
Initial dose: 1.6 mcg/kg orally once a day


Individuals over 50 years and/or Patients with Cardiovascular Disease:
Initial dose: 12.5 to 25 mcg orally once a day

Severe Longstanding Hypothyroidism:
Initial dose: 12.5 to 25 mcg orally once a day

MAINTENANCE DOSE: Approximately 1.6 mcg/kg/day is a full replacement dose
MAXIMUM dose: 200 to 300 mcg/day (doses greater than 200 mcg/day are seldom needed; doses greater than 300 mcg/day are rarely needed and may indicate poor compliance, malabsorption, drug interactions, or a combination of these factors)

Secondary (PITUITARY) OR Tertiary (HYPOTHALAMIC) Hypothyroidism:

Comments:

Use: As replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism

Usual Adult Dose for TSH Suppression

TSH levels should generally be suppressed to below 0.1 IU/L


Comments:

Use: As an adjunct to surgery and radioiodine therapy in the management of thyrotropin-
dependent well-differentiated thyroid cancer.

Usual Adult Dose for Myxedema Coma

Parenteral Formulation:


Comment:

Use: For the treatment of myxedema coma.

Usual Geriatric Dose for Hypothyroidism

Initial dose: 12.5 to 25 mcg orally once a day

Maintenance dose: Full replacement doses may be less than 1 mcg/kg/day
Maximum dose: 200 to 300 mcg/day (doses greater than 200 mcg/day are seldom needed; doses greater than 300 mcg/day are rarely needed and may indicate poor compliance, malabsorption, drug interactions, or a combination of these factors)

Comments:

Use: As replacement therapy in primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) congenital or acquired hypothyroidism

Usual Pediatric Dose for Hypothyroidism

0 to 3 months: 10 to 15 mcg/kg orally once a day
3 to 6 months: 8 to 10 mcg/kg orally once a day
6 to 12 months: 6 to 8 mcg/kg orally once a day
1 to 5 years: 5 to 6 mcg/kg orally once a day
6 to 12 years: 4 to 5 mcg/kg orally once a day
12 years or older and incomplete growth and puberty: 2 to 3 mcg/kg orally once a day
12 years or older with growth and puberty complete: 1.6 mcg/kg orally once a day

Newborns (0 to 3 months) at Risk for Cardiac Failure: Consider a lower initial dose; increase dose every 4 to 6 weeks as needed based on clinical and laboratory response

Pediatric Patients at Risk for Hyperactivity: Initial dose should be one-fourth the recommended full replacement dose; increase weekly by one-fourth to the full recommended replacement dose

Comments:


Use: For the treatment of congenital or acquired hypothyroidism.

Renal Dose Adjustments

No adjustment recommended

Liver Dose Adjustments

No adjustment recommended

Dose Adjustments

Myxedema Coma: Elderly and Patients with Cardiovascular Disease: IV use is associated with cardiac toxicity, therefore, doses at the lower end of the dose range should be used in these populations.

Pregnancy:
New Onset Hypothyroidism:


Therapeutic drug monitoring/range:

Precautions

US BOXED WARNING: NOT FOR TREATMENT OF OBESITY OR FOR WEIGHT LOSS


NARROW THERAPEUTIC INDEX:
Recommendations:

CONTRAINDICATIONS:

Consult WARNINGS section for additional precautions.

Dialysis

Very little drug is removed by dialysis because T4 is highly protein bound.

Other Comments

Administration advice:


CAPSULES: For patients 6 years or older; Swallow whole; do not crush, chew, or cut
LEVO-T Tablets: Take with a full glass of water as tablet may rapidly disintegrate
THYQUIDITY Oral Solution: Use calibrated oral syringe to measure and administer dose
TIROSINT-SOL Oral Solution in Unit Dos Ampules: May dilute or mix in water prior to administering OR squeeze directly into mouth or onto a spoon; do not mix or dilute with any liquid other than water

For Administration to Infants and Children Unable to Swallow Intact Tablets:

Storage requirements:

Reconstitution/preparation techniques:

IV compatibility: Do not add to other IV fluids

General:
when switching patients between oral and parenteral product as accurate dosing conversion has not been studied.

Monitoring: Closely monitor to avoid over and undertreatment:

Patient advice:

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.