Synthroid (Page 6 of 7)

Newborns

The recommended starting dose of levothyroxine sodium in newborn infants is 10-15 mcg/kg/day. A lower starting dose (e.g., 25 mcg/day) should be considered in infants at risk for cardiac failure, and the dose should be increased in 4-6 weeks as needed based on clinical and laboratory response to treatment. In infants with very low (< 5 mcg/dL) or undetectable serum T4 concentrations, the recommended initial starting dose is 50 mcg/day of levothyroxine sodium.

Infants and Children

Levothyroxine therapy is usually initiated at full replacement doses, with the recommended dose per body weight decreasing with age (see Table 3). However, in children with chronic or severe hypothyroidism, an initial dose of 25 mcg/day of levothyroxine sodium is recommended with increments of 25 mcg every 2-4 weeks until the desired effect is achieved.

Hyperactivity in an older child can be minimized if the starting dose is one-fourth of the recommended full replacement dose, and the dose is then increased on a weekly basis by an amount equal to one-fourth the full-recommended replacement dose until the full recommended replacement dose is reached.

Table 3. Levothyroxine Sodium Dosing Guidelines for Pediatric Hypothyroidism
AGE Daily Dose Per Kg Body Weighta
0-3 months 10-15 mcg/kg/day
3-6 months 8-10 mcg/kg/day
6-12 months 6-8 mcg/kg/day
1-5 years 5-6 mcg/kg/day
6-12 years 4-5 mcg/kg/day
> 12 years but growth and puberty incomplete 2-3 mcg/kg/day
Growth and puberty complete 1.7 mcg/kg/day
a The dose should be adjusted based on clinical response and laboratory parameters (see PRECAUTIONS — Laboratory Tests and Pediatric Use).

Pregnancy

Pregnancy may increase levothyroxine requirements (see PREGNANCY).

Subclinical Hypothyroidism

If this condition is treated, a lower levothyroxine sodium dose (e.g., 1 mcg/kg/day) than that used for full replacement may be adequate to normalize the serum TSH level. Patients who are not treated should be monitored yearly for changes in clinical status and thyroid laboratory parameters.

TSH Suppression in Well-differentiated Thyroid Cancer and Thyroid Nodules

The target level for TSH suppression in these conditions has not been established with controlled studies. In addition, the efficacy of TSH suppression for benign nodular disease is controversial. Therefore, the dose of SYNTHROID used for TSH suppression should be individualized based on the specific disease and the patient being treated.

In the treatment of well-differentiated (papillary and follicular) thyroid cancer, levothyroxine is used as an adjunct to surgery and radioiodine therapy. Generally, TSH is suppressed to < 0.1 mU/L, and this usually requires a levothyroxine sodium dose of greater than 2 mcg/kg/day. However, in patients with high-risk tumors, the target level for TSH suppression may be < 0.01 mU/L.

In the treatment of benign nodules and nontoxic multinodular goiter, TSH is generally suppressed to a higher target (e.g., 0.1 to either 0.5 or 1.0 mU/L) than that used for the treatment of thyroid cancer. Levothyroxine sodium is contraindicated if the serum TSH is already suppressed due to the risk of precipitating overt thyrotoxicosis (see CONTRAINDICATIONS, WARNINGS and PRECAUTIONS).

Myxedema Coma

Myxedema coma is a life-threatening emergency characterized by poor circulation and hypometabolism, and may result in unpredictable absorption of levothyroxine sodium from the gastrointestinal tract. Therefore, oral thyroid hormone drug products are not recommended to treat this condition. Thyroid hormone products formulated for intravenous administration should be administered.

HOW SUPPLIED

SYNTHROID (levothyroxine sodium tablets, USP) are round, color coded, scored and debossed with “SYNTHROID” on one side and potency on the other side. They are supplied as follows:

Strength (mcg) Color NDC# for bottles of90 NDC # for bottles of 100 NDC # for bottles of 1000 NDC # for unit dose cartons of 100
25 orange 0074-4341-90 0074-4341-13 0074-4341-19
50 white 0074-4552-90 0074-4552-13 0074-4552-19 0074-4552-11
75 violet 0074-5182-90 0074-5182-13 0074-5182-19 0074-5182-11
88 olive 0074-6594-90 0074-6594-13 0074-6594-19
100 yellow 0074-6624-90 0074-6624-13 0074-6624-19 0074-6624-11
112 rose 0074-9296-90 0074-9296-13 0074-9296-19
125 brown 0074-7068-90 0074-7068-13 0074-7068-19 0074-7068-11
137 turquoise 0074-3727-90 0074-3727-13 0074-3727-19
150 blue 0074-7069-90 0074-7069-13 0074-7069-19 0074-7069-11
175 lilac 0074-7070-90 0074-7070-13 0074-7070-19
200 pink 0074-7148-90 0074-7148-13 0074-7148-19 0074-7148-11
300 green 0074-7149-90 0074-7149-13 0074-7149-19

All MedLibrary.org resources are included in as near-original form as possible, meaning that the information from the original provider has been rendered here with only typographical or stylistic modifications and not with any substantive alterations of content, meaning or intent.

This site is provided for educational and informational purposes only, in accordance with our Terms of Use, and is not intended as a substitute for the advice of a medical doctor, nurse, nurse practitioner or other qualified health professional.

Privacy Policy | Copyright © 2020. All Rights Reserved.