- Brand Name : Relistor
- Drug Class : Peripherally-Acting Mu-Opioid Receptor Antagonists (PAMORA)
- Medical Author : Divya Jacob, Pharm. D.
- Medical Reviewer : Sarfaroj Khan, BHMS, PGD Health Operations
- _eael_post_view_count : 6
What Is Methylnaltrexone and How Does It Work?
Methylnaltrexone is a prescription medication used for reducing constipation caused by opioid medicine.
- Methylnaltrexone is available under the following different brand names: Relistor
What Are Dosages of Methylnaltrexone?
Adult dosage
Injectable solution
- 8mg/0.4mL vial
- 12mg/0.6mL vial
Tablet
- 150mg
Opioid-Induced Constipation (Advanced Illness Receiving Palliative Care)
Adult dosage
- Weighing between 38-62 kg: 8 mg/dose SC every other day
- Weighing between 62-114 kg: 12 mg/dose SC every other day
- Weighing less than 38 kg or above 114 kg: 0.15 mg/kg/dose SC every other day
Opioid-Induced Constipation (Chronic Noncancer Pain)
Adult dosage
- 12 mg SC every day, OR
- 450 mg orally every day in the morning
Dosage Considerations – Should be Given as Follows:
- See “Dosages”
What Are Side Effects Associated with Using Methylnaltrexone?
Common side effects of Methylnaltrexone include:
- stomach pain,
- gas,
- bloating,
- mild nausea or diarrhea,
- headache,
- muscle spasms,
- dizziness,
- tremors,
- feeling anxious,
- runny nose, or
- chills, sweating, or hot flashes.
Serious side effects of Methylnaltrexone include:
- hives,
- difficult breathing,
- swelling of the face, lips, tongue, or throat,
- a hole or tear in the stomach,
- severe or ongoing diarrhea,
- extreme dizziness,
- bloody or tarry stools,
- coughing up blood or vomit that looks like coffee grounds,
- nausea or vomiting that is new or worsening symptoms, or
- symptoms of opioid medicine withdrawal–anxiety, sweating, chills, yawning, stomach pain, diarrhea.
Rare side effects of Methylnaltrexone include:
- none
This is not a complete list of side effects and other serious side effects or health problems that may occur as a result of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.