Naldemedine is used to treat constipation caused by opioid (narcotic) pain medications in adults with chronic (ongoing) pain that is not caused by cancer. Naldemedine is in a class of medications called peripherally acting mu-opioid receptor antagonists. It works by protecting the bowel from the effects of opioid (narcotic) medications.

Naldemedine comes as a tablet to take by mouth. It is usually taken once a day, with or without food. Take naldemedine at around the same time 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 naldemedine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Tell your doctor if you stop taking opioid medications. If you stop taking opioid medications, you should stop taking naldemedine as well.

Your doctor or pharmacist will give you the manufacturer’s patient information sheet (Medication Guide) when you begin treatment with naldemedine 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 (http://www.fda.gov/Drugs/DrugSafety/ucm085729.htm) to obtain the Medication Guide.

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

Before taking naldemedine,

• Tell your doctor and pharmacist if you are allergic to naldemedine, any other medications, or any of the ingredients in naldemedine 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, you are taking or plan to take. Be sure to mention any of the following: amiodarone (Cordarone); aprepitant (Emend); atazanavir (Reyataz, in Evotaz); captopril (Capoten, in Capozide); carbamazepine (Tegretol); clarithromycin (Biaxin, in PrevPac); cyclosporine (Gengraf, Neoral, Sandimmune); diltiazem (Cardizem, Dilacor, Tiazac); efavirenz (in Atripla, Sustiva); erythromycin (E.E.S., E-Mycin, Erythrocin); fluconazole (Diflucan); itraconazole (Onmel, Sporonax); ketoconazole (Nizoral); other opioid antagonists such as methylnaltrexone (Relistor), naloxegol (Movantik), naloxone (Evzio, in Bunavail, in Suboxone, in Zubsolv), or naltrexone (Revia, in Contrave, in Embeda, Vivitrol); phenytoin (Dilantin, Phenytek); quinidine; rifampin (Rifadin, in Rifamate, Rifater, Rimactane); ritonavir (Norvir, in Kaletra, in Technivie, in Viekira); saquinavir (Invirase): or verapamil (Calan, Covera, Isoptin, Verelan). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with naldemedine, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
• Tell your doctor what herbal products you are taking, especially quercetin and St. John’s wort.
• Tell your doctor if you have or have ever had a gastrointestinal obstruction (a blockage in your bowel). Your doctor will probably tell you not to take naldemedine.
• Tell your doctor if you have or have ever had stomach or bowel problems including stomach ulcer (sores in the lining of the stomach), cancer of the stomach or bowel, Crohn’s disease (a condition in which the body attacks the lining of the digestive tract, causing pain, diarrhea, weight loss, and fever), diverticulitis (small pouches in the lining of the large intestine that can become inflamed), or Ogilvie’s syndrome (a condition in which there is a bulge in the bowel), or liver disease.
• Tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking naldemedine, call your doctor.

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

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

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

• Vomiting
• Diarrhea
• Nausea
• Stomach pain
• Sweating
• Chills
• Feeling cold
• Flushing
• Fever
• Watery eyes
• Runny nose
• Sneezing
• Anxiety
• Irritability
• Uncontrollable shaking of a part of the body
• Fast heartbeat
• Yawning

Some side effects can be serious. If you experience any of these symptoms, stop taking naldemedine and call your doctor immediately or get emergency medical treatment:

• Severe, persistent, or worsening stomach pain
• Difficulty breathing
• Rash

Naldemedine 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 (http://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 light, excess heat and moisture (not in the bathroom).

Store naldemedine in a safe place so that no one else can take it accidentally or on purpose. Keep track of how many tablets are left so you will know if any are missing.

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA’s Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

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 the following:

• Chills
• Sweating
• Diarrhea
• Nausea
• Vomiting
• Stomach pain
• Dizziness

Keep all appointments with your doctor.

This prescription is not refillable. Be sure to schedule appointments with your doctor on a regular basis so that you do not run out of medication.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.