Generic Name: Levothyroxine Tablets (LEE voe thye ROX een)
Brand Name: Levoxyl, Synthroid
- Do not use Synthroid (levothyroxine tablets) to treat obesity or for weight loss. Very bad and sometimes deadly side effects may happen with this medicine if it is taken in large doses or with other drugs for weight loss. Talk with the doctor.
Uses of Synthroid:
- It is used to add thyroid hormone to the body.
- It is used to treat or prevent an enlarged thyroid gland.
- It is used to manage thyroid cancer.
- It may be given to you for other reasons. Talk with the doctor.
What do I need to tell my doctor BEFORE I take Synthroid?
- If you have an allergy to levothyroxine or any other part of Synthroid.
- If you are allergic to any drugs like this one, any other drugs, foods, or other substances. Tell your doctor about the allergy and what signs you had, like rash; hives; itching; shortness of breath; wheezing; cough; swelling of face, lips, tongue, or throat; or any other signs.
- If you have any of these health problems: Overactive thyroid gland, recent heart attack, or weak adrenal gland.
- If you have trouble swallowing.
This is not a list of all drugs or health problems that interact with this medicine.
Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take Synthroid with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.
What are some things I need to know or do while I take Synthroid?
For all patients taking this medicine:
- Tell all of your health care providers that you take Synthroid. This includes your doctors, nurses, pharmacists, and dentists.
- Do not run out of this medicine.
- It may take several weeks to see the full effects.
- If you have high blood sugar (diabetes), you will need to watch your blood sugar closely.
- Have blood work checked as you have been told by the doctor. Talk with the doctor.
- This medicine may cause weak bones (osteoporosis) with long-term use. Talk with your doctor to see if you have a higher chance of weak bones or if you have any questions.
- This medicine may affect how much of some other drugs are in your body. If you are taking other drugs, talk with your doctor. You may need to have your blood work checked more closely while taking Synthroid with your other drugs.
- If you are 65 or older, use this medicine with care. You could have more side effects.
- Tell your doctor if you are pregnant or plan on getting pregnant. You will need to talk about the benefits and risks of using Synthroid while you are pregnant.
- Tell your doctor if you are breast-feeding. You will need to talk about any risks to your baby.
- If giving to your child, the dose of this medicine may need to be changed as your child's weight changes. Have your child's weight checked often. Talk with the doctor before changing your child's dose.
- This medicine may affect growth in children and teens in some cases. They may need regular growth checks. Talk with the doctor.
How is this medicine (Synthroid) best taken?
Use Synthroid as ordered by your doctor. Read all information given to you. Follow all instructions closely.
- Take on an empty stomach 30 minutes before breakfast.
- Some products may cause choking, gagging, or trouble swallowing. These products must be taken with a full glass of water. Ask your pharmacist if you need to take your product with a full glass of water.
- You may crush tablet and mix with 1 or 2 teaspoons (5 or 10 mL) of water.
- Do not take iron products, antacids that have aluminum or magnesium, or calcium carbonate, within 4 hours before or 4 hours after taking this medicine.
- Some other drugs may need to be taken at some other time than Synthroid (levothyroxine tablets). If you take other drugs, check with your doctor or pharmacist to see if you need to take them at some other time than this medicine.
- Some foods like soybean flour (infant formula) may change how Synthroid works in your body. Talk with your doctor.
- If you drink grapefruit juice or eat grapefruit often, talk with your doctor.
- There is more than 1 brand of this medicine. One brand cannot safely be used for the other. The doctor will tell you about any needed change.
- To gain the most benefit, do not miss doses.
- Keep taking Synthroid as you have been told by your doctor or other health care provider, even if you feel well.
What do I do if I miss a dose?
- Take a missed dose as soon as you think about it.
- If it is close to the time for your next dose, skip the missed dose and go back to your normal time.
- Do not take 2 doses at the same time or extra doses.
What are some side effects that I need to call my doctor about right away?
WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:
- Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
- Chest pain or pressure or a fast heartbeat.
- A heartbeat that does not feel normal.
- Shortness of breath, a big weight gain, or swelling in the arms or legs.
- Lump on your neck.
- Feeling more or less hungry.
- A change in weight without trying.
- Loose stools (diarrhea).
- Stomach cramps.
- Throwing up.
- Feeling irritable.
- Feeling nervous and excitable.
- Not able to sleep.
- Bothered by heat.
- Sweating a lot.
- Leg cramps.
- Muscle weakness.
- Period (menstrual) changes.
What are some other side effects of Synthroid?
All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
- Hair loss may happen in some people in the first few months of using this medicine. This most often goes back to normal.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to the FDA at 1-800-FDA-1088. You may also report side effects at http://www.fda.gov/medwatch.
If OVERDOSE is suspected:
If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.
How do I store and/or throw out Synthroid?
- Store at room temperature.
- Protect from light.
- Store in a dry place. Do not store in a bathroom.
- Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
- Check with your pharmacist about how to throw out unused drugs.
Consumer Information Use and Disclaimer
- If your symptoms or health problems do not get better or if they become worse, call your doctor.
- Do not share your drugs with others and do not take anyone else's drugs.
- Keep a list of all your drugs (prescription, natural products, vitamins, OTC) with you. Give this list to your doctor.
- Talk with the doctor before starting any new drug, including prescription or OTC, natural products, or vitamins.
- Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about Synthroid, please talk with your doctor, nurse, pharmacist, or other health care provider.
- If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.
This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about Synthroid. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using Synthroid.
Review Date: November 1, 2017
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- Drug class: thyroid drugs