This information from Lexicomp® explains what you need to know about this medication, including what it’s used for, how to take it, its side effects, and when to call your healthcare provider.
Brand Names: US
Brand Names: Canada
- This drug may cause a prolonged QT interval (a type of heartbeat that is not normal). If this happens, the chance of other unsafe abnormal heartbeats may be raised. Sudden deaths have happened in people taking this drug. Do not take this drug if you have low calcium, potassium, or magnesium levels or if you have ever had a long QT on ECG. Your heartbeat will be watched often with an ECG. Talk with your doctor.
- Have blood work checked as you have been told by the doctor. Talk with the doctor.
- Do not take this drug if you are taking certain other drugs, including any drugs that can raise the chance of a prolonged QT interval (a type of heartbeat that is not normal). There are many drugs that interact with this drug. Talk with your doctor and pharmacist to make sure it is safe to take this drug with all of your drugs.
What is this drug used for?
- It is used to treat thyroid cancer.
What do I need to tell my doctor BEFORE I take this drug?
- If you are allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
- If you have any of these health problems: Kidney disease or liver disease.
- If you have ever had any of these health problems: A heartbeat that is not normal, slow heartbeat, or weak heart (heart failure).
- If you have recently thrown up blood.
- If you take any drugs (prescription or OTC, natural products, vitamins) that must not be taken with this drug, like certain drugs that are used for HIV, infections, or seizures. There are many drugs that must not be taken with this drug.
- If you are taking any drugs used for a heartbeat that is not normal.
- If you are pregnant or may be pregnant. This drug may cause harm to an unborn baby. A pregnancy test will be done before you start this drug to show that you are NOT pregnant. If you may become pregnant, you must use birth control while taking this drug and for some time after the last dose. Ask your doctor how long to use birth control. If you get pregnant, call your doctor right away.
- If you are breast-feeding. Do not breast-feed while you take this drug or for 4 months after your last dose.
This is not a list of all drugs or health problems that interact with this drug.
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 this drug 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 this drug?
- Tell all of your health care providers that you take this drug. This includes your doctors, nurses, pharmacists, and dentists.
- Avoid driving and doing other tasks or actions that call for you to be alert or have clear eyesight until you see how this drug affects you.
- A very bad and sometimes deadly brain problem called posterior reversible encephalopathy syndrome (PRES) has happened with this drug. Call your doctor right away if you have signs like feeling confused, lowered alertness, change in eyesight, loss of eyesight, seizures, or very bad headache.
- Heart failure has happened with this drug, as well as heart failure that has gotten worse in people who already have it. Sometimes, this has been deadly. Tell your doctor if you have heart disease. Call your doctor right away if you have shortness of breath, a big weight gain, a heartbeat that is not normal, or swelling in the arms or legs that is new or worse.
- Very bad and sometimes deadly brain blood vessel problems have happened with this drug. Talk with your doctor.
- Low white blood cell counts have happened with this drug. This may lead to a higher chance of getting an infection. Call your doctor right away if you have signs of infection like fever, chills, or sore throat.
- You may bleed more easily. Be careful and avoid injury. Use a soft toothbrush and an electric razor. Rarely, some bleeding problems have been deadly.
- Call your doctor right away if you have any signs of bleeding problems, like bruising; black, tarry, or bloody stools; bleeding gums; blood in the urine; coughing up blood; cuts that take a long time to stop bleeding; feel dizzy; feeling very tired or weak; nosebleeds; pain or swelling; throwing up blood or throw up that looks like coffee grounds; or very bad headache.
- If you get diarrhea, you will need to make sure to avoid getting dehydrated. Drink plenty of fluids and watch for weight loss. Talk with your doctor.
- Kidney problems like kidney failure have happened with this drug. Tell your doctor if you have ever had kidney problems.
- High blood pressure has happened with this drug. Have your blood pressure checked as you have been told by your doctor.
- You may get sunburned more easily while taking this drug and for 4 months after your last dose. Avoid sun, sunlamps, and tanning beds. Use sunscreen and wear clothing and eyewear that protects you from the sun.
- Some people have had lung problems with this drug. Sometimes, this has been deadly. Call your doctor right away if you have signs of lung problems like shortness of breath or other trouble breathing, cough that is new or worse, or fever.
- This drug may affect fertility. Fertility problems may lead to not being able to get pregnant or father a child. If you plan to get pregnant or father a child, talk with your doctor before taking this drug.
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, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
- Signs of low thyroid levels like constipation; not able to handle cold; memory problems; mood changes; or a burning, numbness, or tingling feeling that is not normal.
- Signs of high blood pressure like very bad headache or dizziness, passing out, or change in eyesight.
- Signs of electrolyte problems like mood changes; confusion; muscle pain, cramps, or spasms; weakness; shakiness; change in balance; an abnormal heartbeat; seizures; loss of appetite; or severe upset stomach or throwing up.
- Signs of kidney problems like unable to pass urine, change in how much urine is passed, blood in the urine, or a big weight gain.
- Chest pain or pressure, a fast heartbeat, or an abnormal heartbeat.
- Weakness on 1 side of the body, trouble speaking or thinking, change in balance, drooping on one side of the face, or blurred eyesight.
- Depression or other mood changes.
- Muscle or joint pain.
- Change in eyesight.
- Pimples (acne).
- Dry skin.
- A severe skin reaction (Stevens-Johnson syndrome/toxic epidermal necrolysis) may happen. It can cause severe health problems that may not go away, and sometimes death. Get medical help right away if you have signs like red, swollen, blistered, or peeling skin (with or without fever); red or irritated eyes; or sores in your mouth, throat, nose, or eyes.
What are some other side effects of this drug?
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.
- Feeling tired or weak.
- Stomach pain.
- Dry mouth.
- Change in nails.
- Change in taste.
- Muscle spasm.
- Signs of a common cold.
- Diarrhea, throwing up, upset stomach, and decreased appetite are common with this drug. If these happen, talk with your doctor about ways to lower these side effects. Call your doctor right away if any of these effects bother you, do not get better, or are severe.
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 your national health agency.
You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.
How is this drug best taken?
Use this drug as ordered by your doctor. Read all information given to you. Follow all instructions closely.
- Take with or without food.
- Keep taking this drug as you have been told by your doctor or other health care provider, even if you feel well.
- You will need to take special care when handling this drug. Check with the doctor or pharmacist to see how to handle this drug.
- Swallow whole. Do not chew, break, or crush.
- If needed, you may put your dose in 2 ounces (60 mL) of water. Mix for 10 minutes or until the drug is in very small pieces and drink. This drug will not dissolve all the way. Rinse the cup with 4 ounces (120 mL) of water and drink.
- If the tablet is crushed or broken, do not touch the contents. If you do touch the contents or get it in your eyes, wash hands or eyes right away.
- Those who have feeding tubes may use this drug. Use as you have been told. Flush the feeding tube after this drug is given.
- This drug may affect how wounds heal. If you need to have surgery, you may need to stop this drug before surgery. Start taking it again after surgery as you have been told by your doctor. Call your doctor right away if you have a wound that does not heal or any other wound problems.
What do I do if I miss a dose?
- Take a missed dose as soon as you think about it.
- If it is less than 12 hours until the 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.
How do I store and/or throw out this drug?
- Store at room temperature 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.
- Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.
General drug facts
- 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.
- Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your doctor, nurse, pharmacist, or other health care provider.
- This drug comes with an extra patient fact sheet called a Medication Guide. Read it with care. Read it again each time this drug is refilled. If you have any questions about this drug, please talk with the doctor, 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.
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