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What is Synthroid
LevothyroxineThe Generic name of this drug
Treatment SummaryLevothyroxine, also known as L-thyroxine or Synthroid, is a synthetic form of thyroxine which is a hormone naturally produced by the thyroid gland. It is used to treat hypothyroidism, a condition where the body does not make enough thyroid hormones. Common symptoms of hypothyroidism include fatigue, increased heart rate, depression, dry skin and hair, muscle cramps, constipation, weight gain, memory issues, and difficulty with cold temperatures. Levothyroxine helps to restore normal levels of hormones in the body and can be prescribed to both adults and children. It is usually more effective
Thyrolaris the brand name
Synthroid Overview & Background
Brand Name
Generic Name
First FDA Approval
How many FDA approvals?
Thyrolar
Levothyroxine
1969
1177
Approved as Treatment by the FDA
Levothyroxine, also known as Thyrolar, is approved by the FDA for 3 uses including Malignant Neoplasms and Hypothyroidism .Malignant Neoplasms
Hypothyroidism
Helps manage Hypothyroidism
euthyroid Goitre
Helps manage euthyroid Goitre
Effectiveness
How Synthroid Affects PatientsLevothyroxine is a synthetic hormone that replaces the natural hormone T4 when there is a deficiency. It needs to be carefully adjusted to maintain the right levels in the body, otherwise it can cause problems with growth and development, heart health, reproductive function, thinking, emotions, digestive system, and blood sugar and cholesterol. In people with heart problems, levothyroxine should be started with a lower dose since too much can cause a faster heart rate, thicker heart walls, and other issues. Overusing levothyroxine can also lead to weaker bones, especially in post-menopausal women. For those with diabetes, starting or
How Synthroid works in the bodyLevothyroxine is a synthetic form of a hormone produced by the thyroid gland. This hormone increases the metabolic rate of cells in the body, helps with growth and development in fetuses and newborns, and helps adults maintain brain function and body temperature. When there is a deficiency of this hormone, people can experience slow speech, lack of energy, weight gain, hair loss, dry skin, and cold sensitivity. Levothyroxine works by binding to DNA and causing changes in gene expression. It also binds to plasma membrane receptors and can cause downstream effects like angiogenesis and tumor cell proliferation.
When to interrupt dosage
The measure of Synthroid is dependent upon the diagnosed disorder, such as Comatose, Edematous Fibrosclerotic Panniculopathy (Cellulite) and Adiposity. The amount of dosage can be found in the table below, contingent upon the technique of delivery.Condition
Dosage
Administration
Hypothyroidism
, 0.025 mg, 0.05 mg, 0.075 mg, 0.088 mg, 0.1 mg, 0.112 mg, 0.125 mg, 0.15 mg, 0.175 mg, 0.2 mg, 0.3 mg, 0.137 mg, 0.038 mg, 0.019 mg, 0.057 mg, 0.038 mCi, 0.5 mg, 0.2 mg/mL, 0.5 mg/mL, 0.1 mg/mL, 0.0095 mg, 0.013 mg, 0.076 mg, 0.0125 mg, 0.114 mg, 0.15 mg/mL, 0.137 mg/mL, 0.175 mg/mL, 0.112 mg/mL, 0.125 mg/mL, 0.088 mg/mL, 0.075 mg/mL, 0.05 mg/mL, 0.025 mg/mL, 0.013 mg/mL, 0.04 mg/mL, 0.02 mg/mL, 0.0375 mg/mL, 0.0625 mg/mL, 0.044 mg/mL
, Oral, Tablet, Tablet - Oral, Topical, Tablet - Topical, Intravenous, Liquid, Liquid - Intravenous, Intramuscular; Intravenous, Powder, for solution, Powder, for solution - Intramuscular; Intravenous, Injection, powder, lyophilized, for solution, Injection, powder, lyophilized, for solution - Intravenous, Capsule, Capsule - Oral, Solution, Solution - Oral, Injection - Intravenous, Injection, Injection, solution - Intravenous, Injection, solution, Solution - Intramuscular; Intravenous
Malignant Neoplasms
, 0.025 mg, 0.05 mg, 0.075 mg, 0.088 mg, 0.1 mg, 0.112 mg, 0.125 mg, 0.15 mg, 0.175 mg, 0.2 mg, 0.3 mg, 0.137 mg, 0.038 mg, 0.019 mg, 0.057 mg, 0.038 mCi, 0.5 mg, 0.2 mg/mL, 0.5 mg/mL, 0.1 mg/mL, 0.0095 mg, 0.013 mg, 0.076 mg, 0.0125 mg, 0.114 mg, 0.15 mg/mL, 0.137 mg/mL, 0.175 mg/mL, 0.112 mg/mL, 0.125 mg/mL, 0.088 mg/mL, 0.075 mg/mL, 0.05 mg/mL, 0.025 mg/mL, 0.013 mg/mL, 0.04 mg/mL, 0.02 mg/mL, 0.0375 mg/mL, 0.0625 mg/mL, 0.044 mg/mL
, Oral, Tablet, Tablet - Oral, Topical, Tablet - Topical, Intravenous, Liquid, Liquid - Intravenous, Intramuscular; Intravenous, Powder, for solution, Powder, for solution - Intramuscular; Intravenous, Injection, powder, lyophilized, for solution, Injection, powder, lyophilized, for solution - Intravenous, Capsule, Capsule - Oral, Solution, Solution - Oral, Injection - Intravenous, Injection, Injection, solution - Intravenous, Injection, solution, Solution - Intramuscular; Intravenous
Comatose
, 0.025 mg, 0.05 mg, 0.075 mg, 0.088 mg, 0.1 mg, 0.112 mg, 0.125 mg, 0.15 mg, 0.175 mg, 0.2 mg, 0.3 mg, 0.137 mg, 0.038 mg, 0.019 mg, 0.057 mg, 0.038 mCi, 0.5 mg, 0.2 mg/mL, 0.5 mg/mL, 0.1 mg/mL, 0.0095 mg, 0.013 mg, 0.076 mg, 0.0125 mg, 0.114 mg, 0.15 mg/mL, 0.137 mg/mL, 0.175 mg/mL, 0.112 mg/mL, 0.125 mg/mL, 0.088 mg/mL, 0.075 mg/mL, 0.05 mg/mL, 0.025 mg/mL, 0.013 mg/mL, 0.04 mg/mL, 0.02 mg/mL, 0.0375 mg/mL, 0.0625 mg/mL, 0.044 mg/mL
, Oral, Tablet, Tablet - Oral, Topical, Tablet - Topical, Intravenous, Liquid, Liquid - Intravenous, Intramuscular; Intravenous, Powder, for solution, Powder, for solution - Intramuscular; Intravenous, Injection, powder, lyophilized, for solution, Injection, powder, lyophilized, for solution - Intravenous, Capsule, Capsule - Oral, Solution, Solution - Oral, Injection - Intravenous, Injection, Injection, solution - Intravenous, Injection, solution, Solution - Intramuscular; Intravenous
euthyroid Goitre
, 0.025 mg, 0.05 mg, 0.075 mg, 0.088 mg, 0.1 mg, 0.112 mg, 0.125 mg, 0.15 mg, 0.175 mg, 0.2 mg, 0.3 mg, 0.137 mg, 0.038 mg, 0.019 mg, 0.057 mg, 0.038 mCi, 0.5 mg, 0.2 mg/mL, 0.5 mg/mL, 0.1 mg/mL, 0.0095 mg, 0.013 mg, 0.076 mg, 0.0125 mg, 0.114 mg, 0.15 mg/mL, 0.137 mg/mL, 0.175 mg/mL, 0.112 mg/mL, 0.125 mg/mL, 0.088 mg/mL, 0.075 mg/mL, 0.05 mg/mL, 0.025 mg/mL, 0.013 mg/mL, 0.04 mg/mL, 0.02 mg/mL, 0.0375 mg/mL, 0.0625 mg/mL, 0.044 mg/mL
, Oral, Tablet, Tablet - Oral, Topical, Tablet - Topical, Intravenous, Liquid, Liquid - Intravenous, Intramuscular; Intravenous, Powder, for solution, Powder, for solution - Intramuscular; Intravenous, Injection, powder, lyophilized, for solution, Injection, powder, lyophilized, for solution - Intravenous, Capsule, Capsule - Oral, Solution, Solution - Oral, Injection - Intravenous, Injection, Injection, solution - Intravenous, Injection, solution, Solution - Intramuscular; Intravenous
Adiposity
, 0.025 mg, 0.05 mg, 0.075 mg, 0.088 mg, 0.1 mg, 0.112 mg, 0.125 mg, 0.15 mg, 0.175 mg, 0.2 mg, 0.3 mg, 0.137 mg, 0.038 mg, 0.019 mg, 0.057 mg, 0.038 mCi, 0.5 mg, 0.2 mg/mL, 0.5 mg/mL, 0.1 mg/mL, 0.0095 mg, 0.013 mg, 0.076 mg, 0.0125 mg, 0.114 mg, 0.15 mg/mL, 0.137 mg/mL, 0.175 mg/mL, 0.112 mg/mL, 0.125 mg/mL, 0.088 mg/mL, 0.075 mg/mL, 0.05 mg/mL, 0.025 mg/mL, 0.013 mg/mL, 0.04 mg/mL, 0.02 mg/mL, 0.0375 mg/mL, 0.0625 mg/mL, 0.044 mg/mL
, Oral, Tablet, Tablet - Oral, Topical, Tablet - Topical, Intravenous, Liquid, Liquid - Intravenous, Intramuscular; Intravenous, Powder, for solution, Powder, for solution - Intramuscular; Intravenous, Injection, powder, lyophilized, for solution, Injection, powder, lyophilized, for solution - Intravenous, Capsule, Capsule - Oral, Solution, Solution - Oral, Injection - Intravenous, Injection, Injection, solution - Intravenous, Injection, solution, Solution - Intramuscular; Intravenous
Cellulite
, 0.025 mg, 0.05 mg, 0.075 mg, 0.088 mg, 0.1 mg, 0.112 mg, 0.125 mg, 0.15 mg, 0.175 mg, 0.2 mg, 0.3 mg, 0.137 mg, 0.038 mg, 0.019 mg, 0.057 mg, 0.038 mCi, 0.5 mg, 0.2 mg/mL, 0.5 mg/mL, 0.1 mg/mL, 0.0095 mg, 0.013 mg, 0.076 mg, 0.0125 mg, 0.114 mg, 0.15 mg/mL, 0.137 mg/mL, 0.175 mg/mL, 0.112 mg/mL, 0.125 mg/mL, 0.088 mg/mL, 0.075 mg/mL, 0.05 mg/mL, 0.025 mg/mL, 0.013 mg/mL, 0.04 mg/mL, 0.02 mg/mL, 0.0375 mg/mL, 0.0625 mg/mL, 0.044 mg/mL
, Oral, Tablet, Tablet - Oral, Topical, Tablet - Topical, Intravenous, Liquid, Liquid - Intravenous, Intramuscular; Intravenous, Powder, for solution, Powder, for solution - Intramuscular; Intravenous, Injection, powder, lyophilized, for solution, Injection, powder, lyophilized, for solution - Intravenous, Capsule, Capsule - Oral, Solution, Solution - Oral, Injection - Intravenous, Injection, Injection, solution - Intravenous, Injection, solution, Solution - Intramuscular; Intravenous
Warnings
Synthroid ContraindicationsCondition
Risk Level
Notes
Pulse Frequency
Do Not Combine
Heart Attack
Do Not Combine
untreated subclinical or overt thryrotoxicosis
Do Not Combine
Adrenal gland hypofunction
Do Not Combine
Common Synthroid Drug Interactions
Drug Name
Risk Level
Description
Abemaciclib
Major
The serum concentration of Abemaciclib can be decreased when it is combined with Levothyroxine.
Bendamustine
Major
The serum concentration of Bendamustine can be decreased when it is combined with Levothyroxine.
Berotralstat
Major
The serum concentration of Berotralstat can be decreased when it is combined with Levothyroxine.
Binimetinib
Major
The serum concentration of Binimetinib can be decreased when it is combined with Levothyroxine.
Bortezomib
Major
The serum concentration of Bortezomib can be decreased when it is combined with Levothyroxine.
Synthroid Toxicity & Overdose RiskIn rats, the lowest dose of a drug that has been found to cause death was 20mg/kg when taken orally. This has been known to cause a state of hypermetabolism similar to an overactive thyroid. Symptoms of this reaction include weight loss, increased appetite, a racing heart, diarrhea, shaking, difficulty sleeping, feeling too hot or feverish, and irregular periods.
Synthroid Novel Uses: Which Conditions Have a Clinical Trial Featuring Synthroid?
15 active studies are currently probing the effects of Synthroid in ameliorating Edematous Fibrosclerotic Panniculopathy (Cellulite), Hypothyroidism and Comatose states.Condition
Clinical Trials
Trial Phases
Cellulite
0 Actively Recruiting
Comatose
0 Actively Recruiting
euthyroid Goitre
0 Actively Recruiting
Malignant Neoplasms
0 Actively Recruiting
Adiposity
7 Actively Recruiting
Not Applicable, Phase 4
Hypothyroidism
7 Actively Recruiting
Not Applicable, Phase 4, Phase 2
Synthroid Reviews: What are patients saying about Synthroid?
5Patient Review
12/13/2018 The endocrinologist I visited not only helped me with my diabetes, but also discovered that I had an issue with my thyroid. They put me on Synthroid and gradually increased the dosage over 3 months. Now, my TSH is in the normal range.
5Patient Review
10/18/2017 Synthroid has been a godsend since my thyroid surgery. I've been taking it regularly since January with few issues. The only downside is that I'm still struggling with hair loss and weight gain, but those are both manageable problems.
5Patient Review
5/17/2020 I've been on Synthroid for over 44 years and it's helped me a lot. I know my lab results always run high, but I feel fine otherwise. It's hard to find a doctor who is willing to treat the "symptoms" instead of relying strictly on lab results, but I'm hopeful that switching to a generic form won't change how I feel currently.
5Patient Review
3/8/2018 I've been taking this medication for 10 years with no issues, except for some thinning hair. It's kept my thyroid levels in check ever since my radioactive iodine treatment. However, I was switched to a generic brand without knowing, and my thyroid levels dropped significantly as a result. Once I went back to the name brand, everything improved again.
2Patient Review
7/23/2019 Unfortunately, I had a really severe allergic reaction to using Synthroid. It contains acacia as well as other ingredients that make it unsafe for me to use. In addition, there was no noticeable difference in my thyroid condition after using this treatment.
2Patient Review
7/23/2019 I had a terrible allergic reaction to the other ingredients in synthroid, like acacia, aluminum, talc and maybe even gluten. I switched to Tirosint which is just pure glycerine and the necessary ingredients--no food dyes or extra junk. It's more effective and much cleaner.
1.7Patient Review
12/30/2017 I've been taking this for eight years now, and my thyroid stimulating hormone levels have been all over the place. Recently, they shot up to 6.7 after I changed my dosage from 88 to 50. I'm tired all the time, easily annoyed, and my weight has gone up, though I was able to lose 20 pounds when I changed my diet. Plus, my hair has been falling out like crazy lately.
1Patient Review
4/5/2022 There are a lot of additives in Synthroid, and many people (myself included) are allergic to them.
1Patient Review
4/12/2019 Since my total thyroidectomy in 2009, I have been dealing with a range of issues including both hypo- and hyper-thyroidism symptoms. This has led to insomnia, pain in my shoulders and neck, agitation, anxiety and depression.
1Patient Review
5/23/2018 I took this medication for three months and found that it didn't help me sleep at all, even when I halved the dosage.
1Patient Review
1/3/2019 Since taking this medication, I have experienced hair loss and weight gain without an increase in appetite. Additionally, I am constantly tired and exhausted.
Patient Q&A Section about synthroid
These questions and answers are submitted by anonymous patients, and have not been verified by our internal team.What does Synthroid do to the body?
"The purpose of Synthroid is to replace the amount of Thyroid hormone that your body is unable to produce. Synthroid is a man-made hormone that is identical to the hormone that your Thyroid gland produces. It is important to maintain optimal Thyroid hormone levels in order to avoid any potential health complications."
Answered by AI
Does Synthroid have side effects?
"The text describes some of the symptoms that may be experienced when suffering from an overactive thyroid, which is a condition in which the thyroid gland produces too much of the hormone thyroxine. Symptoms may include fatigue, increased appetite, weight loss, heat intolerance, fever, excessive sweating, headache, hyperactivity, nervousness, anxiety, irritability, emotional lability, insomnia, tremors, muscle weakness, and muscle spasm."
Answered by AI
Does taking Synthroid cause weight gain?
"If you are taking Synthroid, you may experience weight gain due to an increase in appetite. This may cause you to eat more than usual. You may also gain weight if your dose of Synthroid is not high enough for your body's needs."
Answered by AI
What is the difference between levothyroxine & Synthroid?
"Synthroid is levothyroxine, which is used to treat hypothyroidism. It is a human-made thyroxine hormone, but not always interchangeable with each other."
Answered by AI