The information provided is not a substitute for any medical advice. Therefore, you should always consult with your doctor or pharmacist before using any medication.
What is the dose for an adult?
The initial dose of levothyroxine is 12.5 to 50 mcg once a day. The dosage can be increased in 12.5 to 25 mcg/day increments every 2 to 4 weeks.
In older patients or in younger patients with a history of cardiovascular disease, the dosage should be increased in 12.5 to 25 mcg increments every 3 to 6 weeks.
The initial dose is 50 mcg once a day. The dosage may be increased in 25 to 50 mcg increments every 2 to 4 weeks. The typical maintenance dose is 100 to 200 mcg orally once a day.
Thyroid Suppression Test
2.6 mcg/kg/day for 7 to 10 days.
Initial dose: 300 to 500 mcg IV bolus administered one time.
What is the dose for a child?
- Oral: Give 10 to 15 mcg of levothyroxine per kg of body weight per day; if patient is at risk for development of cardiac failure, begin with a lower dose. In severe cases of hypothyroidism (T4 less than 5 mcg/dL), a higher initial dose of 12 to 17 mcg/kg/day may be considered.
- IV or IM: 50% to 75% of the oral dose.
0 to 3 months:
- 10 to 15 mcg per kg of body weight per day; if the infant is at risk for development of cardiac failure use a lower starting dose of approximately 25 mcg/day; if the initial serum T4 is very low (less than 5 mcg/dL) begin treatment at a higher dosage of approximately 50 mcg/day.
3 to 6 months:
- 8 to 10 mcg/kg or 25 to 50 mcg once per day.
6 to 12 months:
- 6 to 8 mcg/kg or 50 to 75 mcg once per day.
1 to 5 years:
- 5 to 6 mcg/kg or 75 to 100 mcg once per day.
6 to 12 years:
- 4 to 5 mcg/kg or 100 to 125 mcg once per day.
- 2 to 3 mcg/kg or greater than or equal to 150 mcg once per day.
Patients in which growth and puberty are complete: 1.7 mcg/kg once per day.
For chronic or severe hypothyroidism: 25 mcg once per day and increase dosage as needed in increments of 25 mcg every 2 to 4 weeks until the desired effect is achieved.
How is levothyroxine available?
Levothyroxine is available in the following dosage forms and strengths:
- Tablet: 212.5 mcg, 5 mcg, 50 mcg, 100 mcg, 150 mcg
- Oral solution: 100 mcg/5 mL
- Solutions for injection: 100 mcg/5 mL
What should I do in case of an emergency or overdose?
In case of an emergency or an overdose, call your local emergency services or go to the nearest emergency room.
What should I do if I miss a dose?
If you miss a dose, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.