Treats constipation caused by pain medicines called opioids, in patients with severe illness. This medicine is used when other medicines for constipation (such as laxatives) have not worked well.
There may be other brand names for this medicine.
When This Medicine Should Not Be Used
You should not use this medicine if you have had an allergic reaction to methylnaltrexone, or if you have a bowel blockage.
How to Use This Medicine
- Your doctor will prescribe your exact dose and tell you how often it should be given. This medicine is given as a shot under your skin.
- This medicine comes with patient instructions. Read and follow these instructions carefully. Ask your doctor or pharmacist if you have any questions.
- You may be taught how to give your medicine at home. Make sure you understand all instructions before giving yourself an injection. Do not use more medicine or use it more often than your doctor tells you to.
- You will be shown the body areas where this shot can be given. Use a different body area each time you give yourself a shot. Keep track of where you give each shot to make sure you rotate body areas.
- Use a new needle and syringe each time you inject your medicine.
If a dose is missed:
- Call your doctor or pharmacist for instructions.
How to Store and Dispose of This Medicine
- If you store this medicine at home, keep it at room temperature, away from heat and direct light. Do not freeze.
- Ask your pharmacist, doctor, or health caregiver about the best way to dispose of any leftover medicine, containers, and other supplies. You will also need to throw away old medicine after the expiration date has passed.
- Throw away used needles in a hard, closed container that the needles cannot poke through. Keep this container away from children and pets.
- Keep all medicine away from children and never share your medicine with anyone.
Drugs and Foods to Avoid
Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
Warnings While Using This Medicine
- Make sure your doctor knows if you are pregnant or breastfeeding, or if you have severe kidney disease or stomach or intestinal ulcers or problems (such as cancer, Ogilvie's syndrome, perforation).
- If you get diarrhea that does not stop or is severe, stop using this medicine and check with your doctor right away.
- Stop using this medicine and check with your doctor right away if you have severe abdominal or stomach pain or cramps; bloody, black, or tarry stools; heartburn; indigestion; nausea; or vomiting of material that looks like coffee grounds. These could be symptoms of a serious bowel problem called intestinal perforation.
- Your doctor will need to check your progress at regular visits while you are using this medicine. Be sure to keep all appointments.
Possible Side Effects While Using This Medicine
Call your doctor right away if you notice any of these side effects:
- Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
- Bloody, black, or tarry stools.
- Increased sweating.
- Severe diarrhea.
- Severe stomach pain.
- Vomiting of material that looks like coffee grounds (severe and continuing).
If you notice these less serious side effects, talk with your doctor:
- Nausea, passing gas, or mild stomach pain.
If you notice other side effects that you think are caused by this medicine, tell your doctor
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088
- Last Reviewed on 06/12/2013
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This page was last updated: June 18, 2013