Mayo Clinic
mayoclinic.org › drugs-supplements › levothyroxine-oral-route › description › drg-20072133
Levothyroxine (oral route) - Side effects & dosage - Mayo Clinic
October 1, 2025 - This medicine is not effective for weight reduction. If taken in large amounts, levothyroxine may cause serious unwanted effects.
Kaiser Permanente
healthy.kaiserpermanente.org › health-wellness › drug-encyclopedia › drug.levothyroxine-50-mcg-tablet.237361
levothyroxine 50 mcg tablet | Kaiser Permanente
Symptoms of low thyroid hormone levels include tiredness, muscle aches, constipation, dry skin, weight gain, slow heartbeat, or sensitivity to cold. Tell your doctor if your condition gets worse or lasts after several weeks of taking this medication. Side effects
Can I take other medications with levothyroxine?
Levothyroxine is known to interact with many other medications (called a drug-drug interaction), but there are different kinds of drug-drug interactions. Some interactions require that drugs not be taken at the same time, while other interactions require more frequent laboratory testing or monitoring of your disease symptoms.
drugs.com
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Levothyroxine: Uses, Dosage, Side Effects - Drugs.com
Can you take thyroid supplements with levothyroxine?
Taking any other medication or supplement with levothyroxine may cause you to need a higher or lower dose of levothyroxine. Even supplements like calcium or iron can affect absorption of levothyroxine.
drugs.com
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Levothyroxine: Uses, Dosage, Side Effects - Drugs.com
Does levothyroxine cause hair loss?
Yes, levothyroxine, the main treatment for a sluggish thyroid gland, may cause hair loss in addition to other side effects. You may experience partial hair loss in the first few months of treatment, but this often resolves and goes back to normal in a short time.
drugs.com
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Levothyroxine: Uses, Dosage, Side Effects - Drugs.com
GoodRx
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Levothyroxine Side Effects You Should Know About - GoodRx
May 1, 2024 - Get emergency treatment right away if your heart symptoms · feel severe or occur with dizziness, chest pain, or shortness of breath. In rare cases, ... Diarrhea is another side effect of levothyroxine that you may experience.
Medical News Today
medicalnewstoday.com › articles › levothyroxine
Levothyroxine: Dosage, side effects, uses, and more
1 week ago - For pregnant women: You may need a higher dosage of levothyroxine. ... The recommended starting dosage is 12.5 to 25 mcg/day.
Drugs.com
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Levothyroxine Side Effects: Common, Severe, Long Term
March 11, 2024 - Get emergency help immediately if any of the following symptoms of overdose occur while taking levothyroxine: ... Some side effects of levothyroxine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine.
Drugs.com
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Levothyroxine: Uses, Dosage, Side Effects - Drugs.com
1 month ago - Taking more than your recommended dose will not make this medicine more effective, and may cause serious side effects. You should not use levothyroxine if you are allergic to glycerin or edetate disodium, or if you have an untreated or uncontrolled adrenal gland disorder.
Medicines For Children
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Levothyroxine for hypothyroidism - Medicines For Children
July 20, 2023 - If your child develops a rash or becomes itchy within 14 days of starting levothyroxine, they may be allergic to the medicine. Contact your doctor straight away. If your child has chest pain or a fast heart beat (they may say that their heart feels fluttery or is racing), contact your doctor straight away or take your child to hospital. Your child may sometimes get side-effects that are not listed above.
MedicineNet
medicinenet.com › levothyroxine › article.htm
Levothyroxine: Generic, Thyroid Uses, Warnings, Side Effects, Dosage
March 15, 2022 - Levothyroxine is a synthetic form of thyroid hormone used to treat hypothyroidism (underactive thyroid), myxedema coma, pituitary TSH suppression, and organ preservation. Common side effects of levothyroxine may include fatigue, increased appetite, weight loss, heat intolerance, fever, excessive sweating, increase in pulse rate, increase in blood pressure, irregular heart rhythm (arrhythmia), palpitations, rapid heartbeat (tachycardia), chest pain (angina pectoris), congestive heart failure, heart attack (myocardial infarction), and others.
Synthroid
synthroid.com › side-effects
Understanding the Possible Side Effects of Synthroid
Taking too much or too little SYNTHROID may lead to negative effects on growth and development, heart function, bone health, reproductive function, mental health, digestive function, and changes in blood sugar and cholesterol metabolism in adult ...
BuzzRx
buzzrx.com › blog › what-are-the-long-term-side-effects-of-levothyroxine
What Are the Long-Term Side Effects of Levothyroxine?
February 11, 2025 - Levothyroxine, used to treat hypothyroidism, can cause some unwanted effects. Learn about the long-term side effects of levothyroxine.
HealthUnlocked
healthunlocked.com › thyroiduk › posts › 151662628 › levothyroxine-side-effects
Levothyroxine side effects: Hi, I am new to the... - Thyroid UK
June 30, 2025 - Started on 25mg on a certain brand, felt unwell, assumed more levothyroxine was needed, increased dose to 50mg, felt overheating anxious unwell, down, not good. Decreased dose to 25mg Wockhardt and after a while felt more like myself again. This time though, I started exercising which had a MASSIVE positive effect.
NHS
nhs.uk › medicines › levothyroxine
Levothyroxine: a medicine for an underactive thyroid (hypothyroidism) - NHS
Levothyroxine starts working straight away, but it may be several weeks before your symptoms start to improve. The most common side effects of levothyroxine are caused by taking a bigger dose than you need.
NCBI
ncbi.nlm.nih.gov › books › NBK539808
Levothyroxine - StatPearls - NCBI Bookshelf
August 28, 2023 - Clinicians should also evaluate the response to levothyroxine by using a validated questionnaire, such as thyroid-related quality of life (ThyPRO) and the underactive thyroid treatment satisfaction questionnaire (ThySRQ).[34][35] If the patient has symptoms of hyperthyroidism, advise the patient to contact the clinician to determine if these are side effects of the medication.
Medscape Reference
reference.medscape.com › tools & reference
Synthroid, Levoxyl (levothyroxine) dosing, indications, interactions, adverse effects, and more
Medscape - Hypothyroidism-specific dosing for Synthroid, Levoxyl (levothyroxine), frequency-based adverse effects, comprehensive interactions, contraindications, pregnancy & lactation schedules, and cost information.
MedlinePlus
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Levothyroxine: MedlinePlus Drug Information
Tell your doctor if you have any ... chest pain, rapid or irregular heartbeat or pulse, uncontrollable shaking of a part of the body, nervousness, anxiety, irritability, difficulty falling asleep or staying asleep, shortness of breath, or excessive sweating...
WebMD
webmd.com › drugs & medications › levothyroxine (levoxyl, synthroid, tirosint, and others)
Levothyroxine (Levoxyl, Synthroid, Tirosint, and others)
December 12, 2024 - Find patient medical information for Levothyroxine (Levoxyl, Synthroid, Tirosint,and others) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings
Poison Control
poison.org › articles › synthroid-levothyroxine
Synthroid (Levothyroxine): Side effects, Interactions, and Overdose | Poison Control
Common brand names of levothyroxine in the US include Synthroid, Levoxyl, Unithroid, and Tirosint. Some common side effects of levothyroxine include fast heart rate, insomnia, fatigue, hair loss, and weight loss.
Wikipedia
en.wikipedia.org › wiki › Levothyroxine
Levothyroxine - Wikipedia
1 week ago - Levothyroxine has a half-life of ... Side effects from excessive doses include weight loss, trouble tolerating heat, sweating, anxiety, trouble sleeping, tremor, and fast heart rate....
Verywell Health
verywellhealth.com › too-much-thyroid-medication-3233271
Signs You're Taking Too Much Levothyroxine for Your Thyroid
December 9, 2025 - Serious side effects that could warrant visiting a provider include wheezing, shortness of breath, hives, rash, and swelling of the hands, feet, ankles, or lower legs. ... There is no single recommended dosage for levothyroxine because each ...
British Thyroid Foundation
btf-thyroid.org › levothyroxine
About levothyroxine
Learn more about levothyroxine as a treatment for hypothyroidism (underactive thyroid)