methylnaltrexone (generic name)

It is used to treat constipation caused by opioids (pain medicine)
(METH il nal TREX one)
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What is this medicine?

METHYLNALTREXONE (METH il nal TREX one) is used to treat constipation caused by opioids (pain medicine). Immediately tell your health care professional if you stop taking your opioid pain medicine.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
  • kidney disease
  • stomach or intestinal blockage or other stomach problems
  • an unusual or allergic reaction to methylnaltrexone, other medicines, foods, dyes, or preservatives
  • pregnant or trying to get pregnant
  • breast-feeding

How should I use this medicine?

This medicine is for injection under the skin. It is usually given by a health care professional in a hospital or clinic setting. If you get this medicine at home, you will be taught how to prepare and give it. Use exactly as directed. Do not take your medicine more often than directed.

It is important that you put your used needles and syringes in a special sharps container. Do not put them in a trash can. If you do not have a sharps container, call your pharmacist or healthcare provider to get one.

Talk to your pediatrician regarding the use of this medicine in children. Special care may be needed.

What if I miss a dose?

This does not apply; this medicine is not for regular use.

What may interact with this medicine?

  • alvimopan
  • naloxone
  • naltrexone

What should I watch for while using this medicine?

Be close to a bathroom after you get this medicine. You may need to use the toilet soon after getting this medicine.

Tell your doctor or healthcare professional if your symptoms do not start to get better or if they get worse.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how this medicine affects you. Do not stand or sit up quickly, especially if you are an older patient. This reduces the risk of dizzy or fainting spells. Alcohol may interfere with the effect of this medicine. Avoid alcoholic drinks.

Your condition will be monitored carefully while you are receiving this medicine.

What side effects may I notice from receiving this medicine?

Side effects that you should report to your doctor or health care professional as soon as possible:
  • severe or persistent diarrhea
  • severe or persistent stomach pain
  • vomiting

Side effects that usually do not require medical attention (report to your doctor or health care professional if they continue or are bothersome):

  • dizziness
  • gas
  • nausea
  • stomach cramps

Where should I keep my medicine?

Keep out of the reach of children.

Store at room temperature between 20 and 25 degrees C (68 and 77 degrees F). Do not freeze and protect from light. Throw away any unused medicine after the expiration date.

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Last Updated: July 29, 2010
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