Relistor 12mg/0.6ml Inj,0.6ml
It is used to treat constipation caused by some pain drugs.
Drug Class
Opioid-induced constipation treatment
Pharmacologic Class
Peripheral mu-opioid receptor antagonist
Pregnancy Category
Category C
FDA Approved
Apr 2008
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 in the gut, helping you have a bowel movement, without affecting the pain relief from your opioid medication.
How to Use This Medicine
Proper Use of This Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided.
Administration
This medication is administered via injection into the fatty tissue under the skin, typically on the top of the thigh or in the belly area. If someone else is giving you the injection, it may also be given into the outer area of the upper arm. If you are self-administering, your doctor or nurse will instruct you on the proper technique.
Before and after use, wash your hands thoroughly. Rotate the injection site with each dose to avoid irritation. Avoid injecting into skin that is irritated, tender, bruised, red, scaly, hard, scarred, or has stretch marks.
Inspecting the Medication
Do not use the medication if the solution is cloudy, leaking, or contains particles. The solution should be colorless to a faint yellow. If the color changes, do not use the medication.
Single-Use Only
Each prefilled syringe or vial is for one use only. Discard any remaining medication after the dose is administered. Dispose of needles in a designated needle/sharp disposal box. Do not reuse needles or other items. When the box is full, follow local regulations for disposal. If you have any questions, consult your doctor or pharmacist.
Vial Storage
If the medication is drawn from a vial into a syringe, it can be stored at room temperature for up to 24 hours.
Storage and Disposal
Store the medication at room temperature, protected from light and moisture. Do not store in a bathroom. Keep the medication away from freezing temperatures and light. Store all medications in a safe place, out of the reach of children and pets.
Missed Dose
If you take this medication on a regular schedule and miss a dose, take it as soon as you remember. If it is 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 extra doses. If you take this medication as needed, do not take it more frequently than directed by your doctor.
To use this medication correctly, follow your doctor's instructions and read all the information provided.
Administration
This medication is administered via injection into the fatty tissue under the skin, typically on the top of the thigh or in the belly area. If someone else is giving you the injection, it may also be given into the outer area of the upper arm. If you are self-administering, your doctor or nurse will instruct you on the proper technique.
Before and after use, wash your hands thoroughly. Rotate the injection site with each dose to avoid irritation. Avoid injecting into skin that is irritated, tender, bruised, red, scaly, hard, scarred, or has stretch marks.
Inspecting the Medication
Do not use the medication if the solution is cloudy, leaking, or contains particles. The solution should be colorless to a faint yellow. If the color changes, do not use the medication.
Single-Use Only
Each prefilled syringe or vial is for one use only. Discard any remaining medication after the dose is administered. Dispose of needles in a designated needle/sharp disposal box. Do not reuse needles or other items. When the box is full, follow local regulations for disposal. If you have any questions, consult your doctor or pharmacist.
Vial Storage
If the medication is drawn from a vial into a syringe, it can be stored at room temperature for up to 24 hours.
Storage and Disposal
Store the medication at room temperature, protected from light and moisture. Do not store in a bathroom. Keep the medication away from freezing temperatures and light. Store all medications in a safe place, out of the reach of children and pets.
Missed Dose
If you take this medication on a regular schedule and miss a dose, take it as soon as you remember. If it is 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 extra doses. If you take this medication as needed, do not take it more frequently than directed by your doctor.
Lifestyle & Tips
- Maintain adequate hydration.
- Increase dietary fiber intake if appropriate and tolerated.
- Engage in regular physical activity as tolerated.
- Do not take other laxatives unless directed by your doctor.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
For Opioid-Induced Constipation (OIC) in patients with chronic non-cancer pain: 12 mg subcutaneously once daily. For OIC in patients with advanced illness or cancer pain: 8 mg (for patients weighing <38 kg) or 12 mg (for patients weighing 38-114 kg) subcutaneously every other day. Dosing frequency may be increased to once daily if needed and tolerated.
Dose Range:
8 - 12 mg
Condition-Specific Dosing:
chronic_non_cancer_pain_OIC:
12 mg SC once daily
advanced_illness_cancer_pain_OIC:
8 mg SC (for <38 kg) or 12 mg SC (for 38-114 kg) every other day, may increase to once daily if needed.
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established for OIC in chronic non-cancer pain. Limited data for OIC in advanced illness/cancer pain, generally not recommended.
Adolescent:
Not established for OIC in chronic non-cancer pain. Limited data for OIC in advanced illness/cancer pain, generally not recommended.
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed (CrCl 60-89 mL/min)
Moderate:
No adjustment needed (CrCl 30-59 mL/min)
Severe:
For OIC in chronic non-cancer pain (CrCl <30 mL/min): Reduce dose to 8 mg subcutaneously once daily. For OIC in advanced illness/cancer pain (CrCl <30 mL/min): Reduce dose to 8 mg subcutaneously every other day.
Dialysis:
For OIC in chronic non-cancer pain: 8 mg subcutaneously once daily. For OIC in advanced illness/cancer pain: 8 mg subcutaneously every other day. Administer after dialysis.
Hepatic Impairment:
Mild:
No adjustment needed
Moderate:
No adjustment needed
Severe:
For OIC in chronic non-cancer pain (Child-Pugh Class C): Reduce dose to 8 mg subcutaneously once daily. For OIC in advanced illness/cancer pain (Child-Pugh Class C): Reduce dose to 8 mg subcutaneously every other day.
Pharmacology
Mechanism of Action
Methylnaltrexone is a selective antagonist of opioid binding at the mu-opioid receptor. As a quaternary derivative of naltrexone, its positively charged nitrogen limits its ability to cross the blood-brain barrier, thereby acting peripherally to antagonize opioid-induced constipation without reversing central opioid-mediated analgesia.
Pharmacokinetics
Absorption:
Bioavailability:
82% (subcutaneous)
Tmax:
0.5-1.5 hours (subcutaneous)
FoodEffect:
Not applicable (parenteral administration)
Distribution:
Vd:
1.1 L/kg
ProteinBinding:
11-15%
CnssPenetration:
Limited
Elimination:
HalfLife:
8 hours (terminal half-life)
Clearance:
Not available (primarily renal excretion)
ExcretionRoute:
Renal (60-70% unchanged), fecal (10-20%)
Unchanged:
60-70% (in urine)
Pharmacodynamics
OnsetOfAction:
Typically within 30-60 minutes for a bowel movement
PeakEffect:
Not precisely defined for clinical effect, but Tmax for plasma concentration is 0.5-1.5 hours.
DurationOfAction:
Variable, but effects on bowel function can last for several hours to a day.
Confidence:
High
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Attention Immediately
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical help right away:
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 upset stomach or vomiting
Black, tarry, or bloody stools
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any 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 or any other unusual symptoms that bother you or do not go away, contact your doctor:
Stomach pain
Upset stomach or vomiting
Excessive sweating
Gas
Dizziness
Flushing
* Diarrhea (which can be severe; consult your doctor for guidance if you experience 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 about side effects, consult your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, some people may experience severe and potentially life-threatening side effects while taking this medication. If you notice any of the following symptoms, contact your doctor or seek medical help right away:
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 upset stomach or vomiting
Black, tarry, or bloody stools
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any 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 or any other unusual symptoms that bother you or do not go away, contact your doctor:
Stomach pain
Upset stomach or vomiting
Excessive sweating
Gas
Dizziness
Flushing
* Diarrhea (which can be severe; consult your doctor for guidance if you experience 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 about side effects, consult 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 or worsening stomach pain (especially if new or accompanied by fever, chills, or persistent nausea/vomiting) - this could be a sign of a serious bowel problem like perforation.
- Diarrhea that is severe or persistent.
- Signs of opioid withdrawal (e.g., sweating, chills, abdominal pain, anxiety, yawning, runny nose, sneezing, goosebumps, muscle aches) - contact your doctor immediately if these occur, as it may indicate a compromised blood-brain barrier.
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. Be sure to describe the symptoms you experienced.
If you have a bowel blockage or are at increased risk for bowel blockage.
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. Please note that you should 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. They will help determine if it is safe to take this medication in conjunction with your other medications and health issues. 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. Be sure to describe the symptoms you experienced.
If you have a bowel blockage or are at increased risk for bowel blockage.
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. Please note that you should 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. They will help determine if it is safe to take this medication in conjunction with your other medications and health issues. 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 with 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 this may lead to signs of opioid withdrawal. Be aware of the following symptoms, and contact your doctor immediately if you experience sweating, chills, diarrhea, stomach pain, anxiety, irritability, or excessive yawning, as these may indicate opioid withdrawal.
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 with your doctor to discuss the benefits and risks of using this medication during pregnancy. It is crucial to note that using this medication during pregnancy may cause withdrawal symptoms in the unborn baby. Your doctor will need to monitor the unborn baby after administering this medication.
Before combining a laxative with this medication, consult with 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 this may lead to signs of opioid withdrawal. Be aware of the following symptoms, and contact your doctor immediately if you experience sweating, chills, diarrhea, stomach pain, anxiety, irritability, or excessive yawning, as these may indicate opioid withdrawal.
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 with your doctor to discuss the benefits and risks of using this medication during pregnancy. It is crucial to note that using this medication during pregnancy may cause withdrawal symptoms in the unborn baby. Your doctor will need to monitor the unborn baby after administering this medication.
Overdose Information
Overdose Symptoms:
- Exacerbation of known adverse reactions (e.g., abdominal pain, diarrhea, nausea, dizziness).
- Potential for opioid withdrawal symptoms if blood-brain barrier integrity is compromised.
What to Do:
There is no specific antidote for methylnaltrexone overdose. Treatment should be symptomatic and supportive. Monitor for signs of opioid withdrawal. Call 1-800-222-1222 (Poison Control) for advice.
Drug Interactions
Monitoring
Baseline Monitoring
Bowel function history
Rationale: To establish baseline constipation severity and frequency.
Timing: Prior to initiation of therapy
Renal function (CrCl)
Rationale: To determine appropriate dosing for patients with renal impairment.
Timing: Prior to initiation of therapy
Hepatic function (Child-Pugh score)
Rationale: To determine appropriate dosing for patients with severe hepatic impairment.
Timing: Prior to initiation of therapy
Routine Monitoring
Bowel movement frequency and consistency
Frequency: Daily
Target: Regular, soft bowel movements
Action Threshold: Lack of response after several doses, or worsening constipation.
Abdominal pain/discomfort
Frequency: Daily
Target: Minimal to no pain
Action Threshold: New or worsening severe abdominal pain, especially with fever, chills, or persistent nausea/vomiting, which could indicate GI perforation.
Symptom Monitoring
- Severe or persistent abdominal pain
- Nausea
- Vomiting
- Diarrhea
- Dizziness
- Chills
- Sweating
- Signs of opioid withdrawal (rare, but possible if blood-brain barrier is compromised)
Special Patient Groups
Pregnancy
Use during pregnancy should only be considered if the potential benefit justifies the potential risk to the fetus. Animal studies show adverse effects at high doses. Limited human data.
Trimester-Specific Risks:
First Trimester:
Potential for fetal harm based on animal data, but human data are insufficient.
Second Trimester:
Potential for fetal harm based on animal data, but human data are insufficient.
Third Trimester:
Potential for fetal harm based on animal data, but human data are insufficient. Risk of opioid withdrawal in the neonate if the mother's blood-brain barrier is compromised.
Lactation
Methylnaltrexone is excreted into human milk. Due to the potential for serious adverse reactions, including opioid withdrawal in breastfed infants, and the potential for methylnaltrexone to affect the infant's gastrointestinal tract, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.
Infant Risk:
L3 (Moderately safe - potential for infant harm; monitor for signs of opioid withdrawal or GI effects).
Pediatric Use
Safety and effectiveness have not been established in pediatric patients for OIC in chronic non-cancer pain. For OIC in advanced illness/cancer pain, limited data exist, and use is generally not recommended.
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. Dose adjustment based on age alone is not necessary, but consider age-related decline in renal function.
Clinical Information
Clinical Pearls
- Relistor is specifically for opioid-induced constipation; it will not treat other causes of constipation.
- It works peripherally, meaning it should not reverse the pain-relieving effects of opioids in the brain.
- Patients should be advised to discontinue other laxatives when starting Relistor, unless otherwise directed by their physician.
- Monitor for signs of gastrointestinal perforation, especially in patients with underlying GI conditions (e.g., diverticulitis, GI malignancy, peptic ulcer disease).
- Administer subcutaneously in the thigh, abdomen, or upper arm. Rotate injection sites.
Alternative Therapies
- Naloxegol (Movantik) - oral peripheral mu-opioid receptor antagonist
- Naldemedine (Symproic) - oral peripheral mu-opioid receptor antagonist
- Lubiprostone (Amitiza) - chloride channel activator
- Linaclotide (Linzess) - guanylate cyclase-C agonist
- Prucalopride (Motegrity) - selective serotonin-4 (5-HT4) receptor agonist
- Traditional laxatives (e.g., stool softeners, osmotic laxatives, stimulant laxatives) - often tried first line.
Cost & Coverage
Average Cost:
Varies, typically high per 12mg/0.6ml single-dose pre-filled syringe
Insurance Coverage:
Tier 3 or Specialty Tier (requires prior authorization)
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. 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, which provides crucial information for patients. Please read this guide carefully and review it again whenever you receive a refill of this medication. If you have any questions or concerns about this medication, we encourage you to discuss them with your doctor, pharmacist, or other healthcare provider. 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 details about the medication taken, the quantity, and the time it occurred.