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.

Side Effects Of Naldemedine

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.

Warnings & Precautions

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.

Dosage Of Naldemedine

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.


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.


All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.