Methylnaltrexone (oral/injection)

Generic name: methylnaltrexone (oral/injection) [ METh-IL-nal-TREX-own ]
Brand name: Relistor
Dosage forms: oral tablet (150 mg); subcutaneous solution (12 mg/0.6 mL; 8 mg/0.4 mL)
Drug class:Peripheral opioid receptor antagonists

Medically reviewed by Drugs.com on Jan 29, 2021. Written by Cerner Multum.

What is methylnaltrexone?

Methylnaltrexone reduces constipation caused by using opioid medicine. Methylnaltrexone treats constipation without reducing the pain-relieving effects of the opioid.

Methylnaltrexone is given to adults who use opioid medicine to treat severe chronic pain that is not caused by cancer. Methylnaltrexone injection is also for use in adults who have advanced illness and are receiving palliative care (treatment to relieve suffering and improve quality of life during a serious illness).

Methylnaltrexone may also be used for purposes not listed in this medication guide.

Warnings

Methylnaltrexone may cause a perforation (a hole or tear) within your stomach or intestines. Stop using methylnaltrexone and get medical help right away if you have severe stomach pain.

While using this medicine, you may have symptoms of opioid withdrawal, such as anxiety, sweating, chills, yawning, stomach pain, or diarrhea.

Stop using methylnaltrexone and call your doctor if you have severe or ongoing diarrhea.

Before taking this medicine

You should not use methylnaltrexone if you have a blockage in your stomach or intestines.

Tell your doctor if you have ever had:

• a stomach ulcer;

• perforation (a hole or tear) in your stomach or intestines;

• kidney disease;

• liver disease; or

• colitis or other intestinal disorder such as Crohn's disease, diverticulitis, or Ogilvie's syndrome.

Tell your doctor if you are pregnant. If you use methylnaltrexone while you are pregnant, your newborn baby could have withdrawal symptoms.

You should not breastfeed while using methylnaltrexone.

Methylnaltrexone is not approved for use by anyone younger than 18 years old.

How should I use methylnaltrexone?

Stop using laxatives before you start using methylnaltrexone.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as ...