Sodium Iodide I131

Adult Medication

Brand Names: US


What is this drug used for?

  • It is used to treat an overactive thyroid gland.
  • It is used to treat 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 this drug?

  • If you have an allergy to sodium iodide or any other part of this drug.
  • 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: Loose stools or throwing up.
  • If you are pregnant or may be pregnant. Do not take this drug if you are pregnant.
  • If you are breast-feeding. Do not breast-feed after getting this drug for as long as your doctor has told you.
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.
  • Follow what you were told to do by your doctor after leaving the hospital to keep from exposing others to this drug.
  • Have blood work checked as you have been told by the doctor. Talk with the doctor.
  • Follow up with the doctor as you have been told.
  • Other drugs may be given before this drug to help avoid side effects.
  • Health problems caused by radiation have happened with this drug. Sometimes, these have been deadly. Talk with the doctor.
  • This drug may add to the chance of getting some types of cancer. Talk with the doctor.
  • If you are allergic to sulfites, talk with your doctor. Some products have sulfites.
  • Neck tenderness or swelling, pain with swallowing, sore throat, and cough may happen a few days after treatment starts. Talk with the doctor if these bother you or do not go away.
  • Pass urine often. You need to empty your bladder often. Drinking lots of liquids will help.
  • Use the toilet instead of a urinal.
  • Use the same toilet each time you use the bathroom in your home. Sit down on the toilet to urinate to keep urine from splashing or spraying. Flush the toilet a few times after each use.
  • Wash your hands after using the toilet.
  • Clean up any spilled urine, feces, or blood right away. Avoid touching.
  • If urine, feces, or blood gets onto clothing, wash the clothing by itself.
  • This drug may affect sperm in men. This may affect being able to father a child. Talk with the doctor.
  • If you are a man and have sex with a female who could get pregnant, protect her from pregnancy during care and for some time after care ends. Use 2 kinds of birth control that you can trust. Talk with your doctor to see how long to use birth control after you stop this drug.
  • If you are a man and your sex partner gets pregnant while you take this drug or within several months after your last dose, call your doctor right away.
  • This drug may cause fertility problems. This may affect being able to have children. Talk with the doctor.
  • This drug may cause harm to the unborn baby if you take it while you are pregnant.
  • If you are able to get pregnant, a pregnancy test will be done to show that you are NOT pregnant before starting this drug. Talk with your doctor.
  • Use 2 kinds of birth control that you can trust to prevent pregnancy during care and for some time after care ends. Talk with your doctor to see how long to use birth control after you stop this drug.
  • If you get pregnant while taking this drug or within several months after the last dose, call your doctor right away.

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 new or worse thyroid problems like a change in weight without trying, feeling nervous and excitable, feeling restless, feeling very weak, hair thinning, low mood (depression), neck swelling, not able to focus, not able to handle heat or cold, period (menstrual) changes, shakiness, or sweating.
  • Chest pain or pressure or a fast heartbeat.
  • Dizziness.
  • Shortness of breath.
  • Fever or chills.
  • Sore throat.
  • Feeling very tired or weak.
  • Any unexplained bruising or bleeding.
  • Dry eyes.
  • Dry mouth.
  • Mouth pain.
  • Swelling.

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:
  • Upset stomach or throwing up.
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.

How is this drug best taken?

Use this drug as ordered by your doctor. Read all information given to you. Follow all instructions closely.
  • Your doctor will give this drug.
  • Drink lots of noncaffeine liquids after using this drug unless told to drink less liquid by your doctor.

What do I do if I miss a dose?

  • Call your doctor to find out what to do.

How do I store and/or throw out this drug?

  • If you need to store this drug at home, talk with your doctor, nurse, or pharmacist about how to store it.

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.
  • 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.
  • 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.
  • 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.
  • 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.

Consumer Information Use and Disclaimer

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 this medicine. 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 this medicine.

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