Generic vs. Name-Brand Levothyroxine

Study Overview
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Brief Summary
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This study compares two different brands of thyroxine (thyroid hormone). Currently, pharmacists may be substituting generic formulations of thyroid hormone without your doctor knowing about this. Although a small difference in thyroid function is not significant in most healthy children, adolescents and adults, in infants and toddlers even a small difference in thyroid function can have important harmful consequences on brain development. The purpose of the present study is to learn whether the difference between brands of thyroid hormone that are currently being substituted is sufficient to cause a difference in thyroid function.

Detailed Description
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This study is an unblinded, randomized controlled cross-over study, which involves taking 2 different forms of levothyroxine sequentially over a 16 week period. Subjects will have a total of 3 visits over this time period. At the first visit, subjects are randomized to receive either generic (Sandoz) levothyroxine or Synthroid (Abbott) brand of levothyroxine. Blood is drawn for baseline thyroid function studies and other markers which are influenced by thyroid hormone at each visit. The second visit is the cross-over visit, and the final visit is a close-out visit, after which each subject will resume taking their previous formulation of levothyroxine.

Official Title
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Generic vs. Name-Brand Levothyroxine: Assessment of Bioequivalence Using TSH as a Marker in Children With Permanent Hypothyroidism

Conditions
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Congenital Hypothyroidism, Hypothyroidism

Intervention / Treatment
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* Drug: Brand Name Levothyroxine (Synthroid)
* Drug: Generic formulation of Levothyroxine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age between 3 and 18 years Diagnosis of Congenital Hypothyroidism with initial TSH > 100 Ability to understand directions and follow all instructions Exclusion Criteria: Not on any drug interfering with absorption of levothyroxine

Ages Eligible for Study
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Minimum Age: 3 Years
Maximum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Brand name levothyroxine (Synthroid)<br>Dose previously demonstrated to normalize thyroid function given daily for 2 months | Drug: Brand Name Levothyroxine (Synthroid)<br>* Randomized crossover study using 8 weeks of brand name levothyroxine (Synthroid, manufactured by Abbott), then 8 weeks of the generic formulation of levothyroxine (manufactured by Sandoz). The dose of medication does not change throughout the duration of the study.<br>* Other names: Levothyroxine;|
| Active Comparator: Generic formulation of Levothyroxine<br>Dosage previously determined to normalize thyroid function given daily for 2 months | Drug: Generic formulation of Levothyroxine<br>* Randomized crossover study using 8 weeks of the generic formulation of levothyroxine (manufactured by Abbott, then 8 weeks of brand name levothyroxine (Synthroid, manufactured by Abbott). The dose of medication does not change throughout the duration of the study.<br>* Other names: No other names;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Thyroid Stimulating Hormone as Primary Endpoint Measured at Initiation of Study, After 8 Weeks of One Drug, and Then 8 Weeks After the Second Drug. |  | 3 points over 16 weeks |