Relistor 150mg Tablets
It is used to treat constipation caused by some pain drugs.
Drug Class
Opioid-induced constipation treatment
Pharmacologic Class
Peripherally-acting mu-opioid receptor antagonist (PAMORA)
Pregnancy Category
Category C
FDA Approved
Sep 2014
DEA Schedule
Not Controlled
Overview
What is this medicine?
Relistor is a medication used to treat constipation caused by opioid pain medicines. It works by blocking the effects of opioids only in your gut, so it helps you have bowel movements without affecting your pain relief.
How to Use This Medicine
Taking Your Medication
To take this medication correctly, follow your doctor's instructions and read all the information provided. Take the medication on an empty stomach, at least 30 minutes before your first meal of the day. Swallow the medication with a full glass of water.
Storing and Disposing of Your Medication
Store the medication at room temperature in a dry place, avoiding the bathroom. Keep it in its original container, and do not remove the antimoisture cube or packet. Store all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of medications, consult your pharmacist. You may also have access to drug take-back programs in your area.
Missing a Dose
If you take this medication regularly and miss a dose, take it as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses. If you take this medication as needed, do not take it more frequently than directed by your doctor.
To take this medication correctly, follow your doctor's instructions and read all the information provided. Take the medication on an empty stomach, at least 30 minutes before your first meal of the day. Swallow the medication with a full glass of water.
Storing and Disposing of Your Medication
Store the medication at room temperature in a dry place, avoiding the bathroom. Keep it in its original container, and do not remove the antimoisture cube or packet. Store all medications in a safe location, out of the reach of children and pets. Dispose of unused or expired medications properly. Do not flush them down the toilet or pour them down the drain unless instructed to do so. If you have questions about disposing of medications, consult your pharmacist. You may also have access to drug take-back programs in your area.
Missing a Dose
If you take this medication regularly and miss a dose, take it as soon as you remember. However, if it's close to the time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses. If you take this medication as needed, do not take it more frequently than directed by your doctor.
Lifestyle & Tips
- Take Relistor 150 mg tablets as three tablets (450 mg total) once daily in the morning.
- Can be taken with or without food.
- Do not take more than one dose per day.
- Continue to take your opioid pain medication as prescribed.
- Maintain adequate fluid intake and fiber in your diet as advised by your doctor.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
450 mg (three 150 mg tablets) orally once daily in the morning
Dose Range:
450 - 450 mg
Condition-Specific Dosing:
opioid_induced_constipation_chronic_non_cancer_pain:
450 mg orally once daily in the morning
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No dosage adjustment necessary (CrCl 60-89 mL/min)
Moderate:
No dosage adjustment necessary (CrCl 30-59 mL/min)
Severe:
Reduce dose to 150 mg orally once daily (CrCl <30 mL/min)
Dialysis:
Reduce dose to 150 mg orally once daily; administer after dialysis on dialysis days
Hepatic Impairment:
Mild:
No dosage adjustment necessary (Child-Pugh A)
Moderate:
No dosage adjustment necessary (Child-Pugh B)
Severe:
Reduce dose to 150 mg orally once daily (Child-Pugh C)
Confidence:
Medium
Pharmacology
Mechanism of Action
Methylnaltrexone is a selective, peripherally-acting mu-opioid receptor antagonist. It blocks the binding of opioids to mu-opioid receptors in the gastrointestinal tract, thereby counteracting opioid-induced decreased gastrointestinal motility and constipation, without reversing the central analgesic effects of opioids because it does not readily cross the blood-brain barrier.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 11-16% (oral)
Tmax:
Approximately 1.5 hours (oral)
FoodEffect:
High-fat meal decreases Cmax by 30% and AUC by 15%, but is not considered clinically significant. Can be taken with or without food.
Distribution:
Vd:
Approximately 1.1 L/kg
ProteinBinding:
Approximately 11-15%
CnssPenetration:
Limited
Elimination:
HalfLife:
Approximately 8-10 hours (oral)
Clearance:
Approximately 0.8 L/h/kg
ExcretionRoute:
Renal (primarily), fecal (minor)
Unchanged:
Approximately 50% (renal), 17% (fecal)
Pharmacodynamics
OnsetOfAction:
Typically within 6-12 hours for oral tablets (first bowel movement)
PeakEffect:
Not directly applicable for a laxative effect, but peak plasma concentrations are reached around 1.5 hours.
DurationOfAction:
Up to 24 hours (consistent with once-daily dosing)
Confidence:
Medium
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Chills
Shakiness
Abdominal swelling
Severe stomach pain or swelling that worsens or persists
Vomiting blood or material that resembles coffee grounds
Persistent or severe nausea and vomiting
Black, tarry, or bloody stools
Other Possible Side Effects
As with any medication, you may experience side effects. While many people have no side effects or only mild ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects, contact your doctor for guidance:
Stomach pain
Excessive sweating
Feeling full
Headache
Muscle spasm
Runny nose
Anxiety
Diarrhea (which can be severe; consult your doctor for advice on managing severe or prolonged diarrhea)
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
While rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Chills
Shakiness
Abdominal swelling
Severe stomach pain or swelling that worsens or persists
Vomiting blood or material that resembles coffee grounds
Persistent or severe nausea and vomiting
Black, tarry, or bloody stools
Other Possible Side Effects
As with any medication, you may experience side effects. While many people have no side effects or only mild ones, it's essential to discuss any concerns with your doctor. If you experience any of the following side effects, contact your doctor for guidance:
Stomach pain
Excessive sweating
Feeling full
Headache
Muscle spasm
Runny nose
Anxiety
Diarrhea (which can be severe; consult your doctor for advice on managing severe or prolonged diarrhea)
Reporting Side Effects
This list is not exhaustive, and you may experience other side effects. If you have questions or concerns, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe, persistent, or worsening abdominal pain
- Fever, chills, nausea, or vomiting (may indicate a serious bowel problem like perforation)
- Symptoms of opioid withdrawal (e.g., sweating, chills, abdominal cramps, diarrhea, anxiety, yawning) - contact your doctor immediately if these occur.
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
If you have a bowel blockage or are at increased risk for developing one.
If you are currently taking another medication similar to this one. If you are unsure, consult your doctor or pharmacist for clarification.
If you are breastfeeding. It is recommended that you do not breastfeed while taking this medication.
This list is not exhaustive, and it is crucial to discuss all your medications (including prescription, over-the-counter, natural products, and vitamins) and health conditions with your doctor and pharmacist. This will help ensure that it is safe for you to take this medication in conjunction with your other treatments and health status. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the symptoms you experienced.
If you have a bowel blockage or are at increased risk for developing one.
If you are currently taking another medication similar to this one. If you are unsure, consult your doctor or pharmacist for clarification.
If you are breastfeeding. It is recommended that you do not breastfeed while taking this medication.
This list is not exhaustive, and it is crucial to discuss all your medications (including prescription, over-the-counter, natural products, and vitamins) and health conditions with your doctor and pharmacist. This will help ensure that it is safe for you to take this medication in conjunction with your other treatments and health status. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. After using this drug, be prepared to have access to a bathroom, as most people experience a bowel movement within a few minutes to a few hours.
Before combining a laxative with this medication, consult your doctor to discuss potential interactions. This medication is specifically designed for patients who are taking opioid pain medications. If you stop taking your opioid pain medication, notify your doctor, as signs of opioid withdrawal may occur. Be aware of symptoms such as excessive sweating, chills, diarrhea, stomach pain, anxiety, irritability, or yawning, and contact your doctor immediately if you experience any of these.
The effectiveness of this medication may be reduced in individuals who have been taking opioid pain medications for less than 4 weeks. If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.
If you are pregnant or planning to become pregnant, consult your doctor to discuss the benefits and risks of using this medication during pregnancy. If this medication is used during pregnancy, it may cause withdrawal symptoms in the unborn baby, and your doctor will need to monitor the baby's health after the medication is administered.
Before combining a laxative with this medication, consult your doctor to discuss potential interactions. This medication is specifically designed for patients who are taking opioid pain medications. If you stop taking your opioid pain medication, notify your doctor, as signs of opioid withdrawal may occur. Be aware of symptoms such as excessive sweating, chills, diarrhea, stomach pain, anxiety, irritability, or yawning, and contact your doctor immediately if you experience any of these.
The effectiveness of this medication may be reduced in individuals who have been taking opioid pain medications for less than 4 weeks. If you are 65 years or older, use this medication with caution, as you may be more susceptible to side effects.
If you are pregnant or planning to become pregnant, consult your doctor to discuss the benefits and risks of using this medication during pregnancy. If this medication is used during pregnancy, it may cause withdrawal symptoms in the unborn baby, and your doctor will need to monitor the baby's health after the medication is administered.
Overdose Information
Overdose Symptoms:
- Exacerbation of known adverse reactions (e.g., abdominal pain, diarrhea, nausea)
- Potential for opioid withdrawal symptoms if blood-brain barrier is compromised
What to Do:
Call 1-800-222-1222 (Poison Control). Treatment is symptomatic and supportive. Monitor for signs of opioid withdrawal.
Drug Interactions
Monitoring
Baseline Monitoring
Renal function (CrCl)
Rationale: To determine appropriate dosing in patients with renal impairment.
Timing: Prior to initiation
Hepatic function (Child-Pugh score)
Rationale: To determine appropriate dosing in patients with severe hepatic impairment.
Timing: Prior to initiation
Bowel habits/constipation severity
Rationale: To establish baseline and assess treatment efficacy.
Timing: Prior to initiation
Routine Monitoring
Bowel movements
Frequency: Daily
Target: Regular, spontaneous bowel movements
Action Threshold: Lack of response after several days, or worsening constipation
Abdominal pain/discomfort
Frequency: Daily
Target: Minimal to no pain
Action Threshold: Severe or worsening abdominal pain, especially with nausea/vomiting (may indicate GI perforation)
Signs of opioid withdrawal
Frequency: Daily, especially early in treatment
Target: Absence of withdrawal symptoms
Action Threshold: Symptoms of opioid withdrawal (e.g., sweating, chills, abdominal cramps, diarrhea, anxiety, yawning) - indicates potential blood-brain barrier penetration or underlying GI pathology.
Symptom Monitoring
- Abdominal pain
- Diarrhea
- Nausea
- Flatulence
- Dizziness
- Symptoms of opioid withdrawal (e.g., sweating, chills, abdominal cramps, diarrhea, anxiety, yawning)
- Signs of gastrointestinal perforation (e.g., severe, persistent, or worsening abdominal pain, fever, chills, nausea, vomiting)
Special Patient Groups
Pregnancy
Use only if the potential benefit justifies the potential risk to the fetus. Limited human data; animal studies show adverse effects at high doses.
Trimester-Specific Risks:
First Trimester:
Limited data, theoretical risk of opioid withdrawal in fetus if maternal opioid dependence is present and drug crosses placenta.
Second Trimester:
Limited data.
Third Trimester:
Limited data, theoretical risk of opioid withdrawal in neonate if maternal opioid dependence is present and drug crosses placenta.
Lactation
Caution is advised. Methylnaltrexone is present in human milk. Monitor breastfed infants for signs of opioid withdrawal (e.g., irritability, poor feeding) or adverse GI effects (e.g., diarrhea). Consider the developmental and health benefits of breastfeeding along with the mother’s clinical need for Relistor and any potential adverse effects on the breastfed infant from Relistor or from the underlying maternal condition.
Infant Risk:
Risk level L3 (Moderate Concern)
Pediatric Use
Safety and effectiveness have not been established in pediatric patients.
Geriatric Use
No overall differences in safety or effectiveness were observed between elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out. No dosage adjustment is required based on age alone, but consider age-related decline in renal function.
Clinical Information
Clinical Pearls
- Relistor is specifically for opioid-induced constipation (OIC) and should not be used for other types of constipation.
- It is a peripherally-acting mu-opioid receptor antagonist, meaning it works in the gut without reversing the pain-relieving effects of opioids in the brain.
- Patients should be advised to discontinue other laxatives once Relistor treatment begins, unless otherwise directed by their healthcare provider.
- Discontinue Relistor if severe or persistent abdominal pain occurs, as this could be a sign of gastrointestinal perforation, especially in patients with underlying GI conditions (e.g., Crohn's disease, diverticulitis, GI malignancy).
- Ensure patients understand the correct dosing for the oral tablets (three 150 mg tablets once daily).
Alternative Therapies
- Naloxegol (Movantik)
- Naldemedine (Symproic)
- Lubiprostone (Amitiza)
- Linaclotide (Linzess)
- Prucalopride (Motegrity)
- Traditional laxatives (e.g., stool softeners, osmotic laxatives, stimulant laxatives) - often used first-line before PAMORAs for OIC.
Cost & Coverage
Average Cost:
Check current per 30 tablets
Insurance Coverage:
Tier 3 or Specialty Tier (varies by plan)
General Drug Facts
If your symptoms or health problems do not improve or worsen over time, it is essential to contact your doctor for further evaluation and guidance. To ensure safe and effective treatment, never share your medication with others or take someone else's medication.
This medication is accompanied by a Medication Guide, a patient fact sheet that provides crucial information about its use. It is vital to read this guide carefully and review it again whenever your prescription is refilled. If you have any questions or concerns about this medication, consult with your doctor, pharmacist, or other healthcare provider for clarification.
In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide detailed information, including the name of the medication taken, the amount consumed, and the time it occurred.
This medication is accompanied by a Medication Guide, a patient fact sheet that provides crucial information about its use. It is vital to read this guide carefully and review it again whenever your prescription is refilled. If you have any questions or concerns about this medication, consult with your doctor, pharmacist, or other healthcare provider for clarification.
In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. When reporting the incident, be prepared to provide detailed information, including the name of the medication taken, the amount consumed, and the time it occurred.