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Levoxyl (Levothyroxine Sodium) - Summary




Thyroid hormones, including LEVOXYL, either alone or with other therapeutic agents, should not be used for the treatment of obesity or for weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects.



–LEVOXYL® (levothyroxine sodium tablets, USP) contain synthetic crystalline L-3,3',5,5'-tetraiodothyronine sodium salt [levothyroxine (T4) sodium]. Synthetic T4 is identical to that produced in the human thyroid gland.

Levothyroxine sodium is used for the following indications:


As replacement or supplemental therapy in congenital or acquired hypothyroidism of any etiology, except transient hypothyroidism during the recovery phase of subacute thyroiditis. Specific indications include: primary (thyroidal), secondary (pituitary), and tertiary (hypothalamic) hypothyroidism and subclinical hypothyroidism. Primary hypothyroidism may result from functional deficiency, primary atrophy, partial or total congenital absence of the thyroid gland, or from the effects of surgery, radiation, or drugs, with or without the presence of goiter.

Pituitary TSH Suppression

In the treatment or prevention of various types of euthyroid goiters (see WARNINGS and PRECAUTIONS), including thyroid nodules (see WARNINGS and PRECAUTIONS), subacute or chronic lymphocytic thyroiditis (Hashimoto's thyroiditis), multinodular goiter (see WARNINGS and PRECAUTIONS) and, as an adjunct to surgery and radioiodine therapy in the management of thyrotropin-dependent well-differentiated thyroid cancer.

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Published Studies Related to Levoxyl (Levothyroxine)

The effect of levothyroxine and selenomethionine on lymphocyte and monocyte cytokine release in women with Hashimoto's thyroiditis. [2011.07]
CONTEXT: No previous study determined monocyte- and lymphocyte-suppressing effects of levothyroxine and selenomethionine and assessed whether their coadministration is superior to treatment with only one of these drugs. OBJECTIVE: Our objective was to compare the effect of levothyroxine and selenomethionine on monocyte and lymphocyte cytokine release and systemic inflammation in patients with Hashimoto's thyroiditis... CONCLUSIONS: Despite affecting different types of inflammatory cells, levothyroxine and selenomethionine exhibit a similar systemic antiinflammatory effect in euthyroid females with Hashimoto's thyroiditis. This action, which correlates with a reduction in thyroid peroxidase antibody titers, may be associated with clinical benefits in the prevention and management of Hashimoto's thyroiditis, particularly in subjects receiving both agents.

Pharmacokinetic equivalence of a levothyroxine sodium soft capsule manufactured using the new food and drug administration potency guidelines in healthy volunteers under fasting conditions. [2011.06]
CONCLUSIONS: The levothyroxine soft capsule formulated with the stricter new potency guideline set forward by the Food and Drug Administration met equivalence criteria in terms of rate and extent of exposure under fasting conditions to the reference tablet formulation. Clinical doses of the capsule formulation can be given using any combination of the commercialized strengths.

Effect of levothyroxine treatment on in vitro fertilization and pregnancy outcome in infertile women with subclinical hypothyroidism undergoing in vitro fertilization/intracytoplasmic sperm injection. [2011.04]
OBJECTIVE: To investigate whether levothyroxine (LT4) treatment has beneficial effects on IVF results and pregnancy outcome in infertile patients with subclinical hypothyroidism undergoing IVF/intracytoplasmic sperm injection (ICSI)...

Metabolic effects of liothyronine therapy in hypothyroidism: a randomized, double-blind, crossover trial of liothyronine versus levothyroxine. [2011]
CONCLUSIONS: The substitution of L-T(3) for L-T(4) at equivalent doses (relative

Effects of evening vs morning levothyroxine intake: a randomized double-blind crossover trial. [2010.12.13]
BACKGROUND: Levothyroxine sodium is widely prescribed to treat primary hypothyroidism. There is consensus that levothyroxine should be taken in the morning on an empty stomach. A pilot study showed that levothyroxine intake at bedtime significantly decreased thyrotropin levels and increased free thyroxine and total triiodothyronine levels. To date, no large randomized trial investigating the best time of levothyroxine intake, including quality-of-life evaluation, has been performed... CONCLUSIONS: Levothyroxine taken at bedtime significantly improved thyroid hormone levels. Quality-of-life variables and plasma lipid levels showed no significant changes with bedtime vs morning intake. Clinicians should consider prescribing levothyroxine intake at bedtime. TRIAL REGISTRATION: isrctn.org Identifier: ISRCTN17436693 (NTR959).

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Clinical Trials Related to Levoxyl (Levothyroxine)

Thyroid Hormone Dose Adjustment in Pregnancy [Recruiting]
Our aim is to compare the safety and efficacy of 2 different empiric levothyroxine dose adjustment recommendations to be made at the first confirmation of pregnancy in women with a history of hypothyroidism. Subjects will be women with a prior diagnosis of hypothyroidism who are taking thyroid hormone replacement and who are less than 8 weeks pregnant. Upon confirmation of pregnancy, subjects will be randomized to increase their weekly thyroid hormone dose by either 2 or 3 tablets (28 or 42%). Thyroid function will be evaluated every two weeks in the first 20 weeks and then again at week 30 and post-partum. Primary endpoints will be the proportion of women in each group who remain euthyroid throughout the first trimester and throughout pregnancy.

Combined Levothyroxine/Liothyronine Supplementation in Hypothyroid Patients With Brain Tumors [Terminated]
Primary Objectives: 1. Assess whether combined treatment with Levothyroxine and Liothyronine improves learning and memory. 2. Explore the relationship between T3 treatment and other domains of cognitive function, quality of life, and mood.

Evaluation of the Efficacy and Safety of Levothyroxine in Brain Death Organ Donors: a Randomized Controled Trial [Recruiting]

Bioequivalence of Two Levothyroxine Tablet Formulations in Healthy Indian Volunteers [Completed]
GSK markets a drug called levothyroxine or T4 that is used to treat patients with hypothyroidism. Till date, the active drug substance or active pharmaceutical ingredient (API) for levothyroxine tablets marketed in India has been obtained from a particular source. GSK India proposes to change the source of the API from the existing source to a new source. Some patients may experience a change in clinical effect when switched from one formulation to another. Therefore this study is being done to understand whether a change in API in levothyroxine tablet has any impact on the clinical effect of the drug. The purpose of this study is to: See how quickly the levothyroxine tablet from the new source (single dose of 600mcg) enters the bloodstream, is distributed in the body, broken down and removed compared to the levothyroxine tablet from the existing source (single dose of 600mcg). Study the effect of single 600mcg doses of levothyroxine tablet from new source and levothyroxine tablet from existing source on TSH level in the blood. Study the safety and side effects of single 600mcg doses of levothyroxine tablet from new source and levothyroxine tablet from existing source.

Desiccated Thyroid Extract and Levothyroxine for Hypothyroidism Treatment [Recruiting]
Our hypothesis is that hypothyroid patients on DTE may have a decrease in symptoms, an improvement of cognitive function, and an increase in sense of well-being/ quality of life equivalently compared with L-T4.

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Reports of Suspected Levoxyl (Levothyroxine) Side Effects

Drug Ineffective (31)Fatigue (27)Alopecia (26)Malaise (24)Hypersensitivity (23)Feeling Abnormal (21)Dizziness (19)Anxiety (19)Rash (17)Insomnia (17)more >>


Based on a total of 24 ratings/reviews, Levoxyl has an overall score of 7.21. The effectiveness score is 7.92 and the side effect score is 8.17. The scores are on ten point scale: 10 - best, 1 - worst. Below are selected reviews: the highest, the median and the lowest rated.

Levoxyl review by 54 year old female patient

Overall rating:  
Effectiveness:   Highly Effective
Side effects:   No Side Effects
Treatment Info
Condition / reason:   hypothyroid problem
Dosage & duration:   0..150mg taken once a day for the period of 35 yrs so far
Other conditions:   none
Other drugs taken:   none
Reported Results
Benefits:   made me feel normal
Side effects:   none
Comments:   i have to take a peel every morning at the same time.if i dont and i forget i get tired its a different kind of tired though.once they stopped giving me the pill for 7 weeks and my hair started falling out i was lethargik i thought i was moving fast but i was moving very slow.i bloated up,i started to think kind of weird.i wanted to sleep all the time i was a real mess.so i take the medication consistantley the best i can.


Levoxyl review by 63 year old female patient

Overall rating:  
Effectiveness:   Considerably Effective
Side effects:   Mild Side Effects
Treatment Info
Condition / reason:   low thyroid levels
Dosage & duration:   100mcg (dosage frequency: once a day) for the period of 2years
Other conditions:   none
Other drugs taken:   none
Reported Results
Benefits:   weight loss, more energy
Side effects:   hair loss at first. subsided after a few months
Comments:   take one pill each morning on an empty stomach with a large glass of water. each 3 months have blood test to determine the need to increase or decrease the medicines dose.


Levoxyl review by 56 year old female patient

Overall rating:  
Effectiveness:   Ineffective
Side effects:   Extremely Severe Side Effects
Treatment Info
Condition / reason:   hypothyroidism
Dosage & duration:   75 mcg (dosage frequency: 1/day) for the period of 10 months
Other conditions:   allergies, high cholesterol
Other drugs taken:   n/a
Reported Results
Benefits:   Hypothyroidism was already causing me to gain weight, this garbage accelerated the weight gain. I eat one fish fillet or chicken breast/day, nothing else, now gaining 3-6 lbs./month! Since I can't find a Dr. who will treat my T3 I'm ordering Cytomel online, from what I've read it's the ticket to eliminate hypo symptoms. Shame on physicians who treat lab results rather than the patient. I don't care what the numbers are, I still feel awful!
Side effects:   FAT
Comments:   Doesn't work! It's the T3!

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Page last updated: 2013-02-10

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