Tenapanor (Ibsrela)

Tenapanor caused life-threatening dehydration (extreme water loss) in young laboratory mice. Children younger than 6 years of age should never take tenapanor. Children 6 to 18 years of age should not take tenapanor.

Your doctor or pharmacist will give you the manufacturer's patient information sheet (Medication Guide) when you begin treatment with tenapanor and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (https://www.fda.gov/Drugs/DrugSafety/ucm085729.htm) or the manufacturer's website to obtain the Medication Guide.

Tenapanor is used to treat irritable bowel syndrome with constipation (IBS-C; a condition that causes stomach pain or cramps, bloating, and infrequent or difficult passage of stools) in adults. Tenapanor is in a class of medications called sodium/hydrogen exchanger (NHE3) inhibitors. It works by increasing the movement of food and waste through the stomach and intestines.

Tenapanor comes as a tablet to take by mouth. It is usually taken twice daily just before breakfast and just before dinner. Take tenapanor at around the same times every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take tenapanor exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Tenapanor controls the symptoms of IBS-C, but it does not cure it. Your constipation symptoms may improve in 1 week, and it may take slightly longer for your stomach pain to improve. Continue to take tenapanor even if you feel well. Do not stop taking tenapanor without talking to your doctor.

Tenapanor is also sometimes used to treat hyperphosphatemia in patients with chronic kidney disease on dialysis. Talk to your doctor about the risks of using this medication for your condition.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

Before taking tenapanor,

• tell your doctor and pharmacist if you are allergic to tenapanor, any other medications, or any of the ingredients in tenapanor tablets. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
• tell your doctor if you have any type of blockage in your stomach or bowels. Your doctor will probably tell you not to take tenapanor.
• tell your doctor if you have or have ever had other medical conditions.
• tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking tenapanor, call your doctor.

Unless your doctor tells you otherwise, continue your normal diet.

Skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

Tenapanor may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• dizziness
• gas
• stomach bloating or tenderness
• mild diarrhea

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately:

• severe diarrhea

Tenapanor may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (https://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Do not remove the desiccant (drying agent) from the bottle, if one has been provided.

Keep all medication out of sight and reach of children as many containers are not child-resistant. Always lock safety caps. Place the medication in a safe location – one that is up and away and out of their sight and reach. https://www.upandaway.org

Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Use a medicine take-back program. Talk to your pharmacist about take-back programs in your community. Visit the FDA's Safe Disposal of Medicines website https://goo.gl/c4Rm4p for more information.

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include:

• diarrhea
• extreme thirst, dry mouth and/or skin, decreased urination, sunken eyes, or fast heartbeat

Keep all appointments with your doctor.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

• Ibsrela^®