Relistor 12mg/0.6ml, Inj(syr)
It is used to treat constipation caused by some pain drugs.
Drug Class
Opioid-induced constipation (OIC) treatment
Pharmacologic Class
Peripherally acting mu-opioid receptor antagonist (PAMORA)
Pregnancy Category
Not available
FDA Approved
Apr 2008
DEA Schedule
Not Controlled
Overview
What is this medicine?
Relistor is an injectable medicine 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 medicine.
How to Use This Medicine
Taking Your Medication Correctly
To ensure you get the most out of your medication, follow your doctor's instructions carefully. Read all the information provided to you and follow the instructions closely.
Administration of Injection Products
This medication is administered via injection into the fatty tissue of the skin, typically on the top of the thigh or in the belly area. If someone else is administering the injection, it may be given in the outer area of the upper arm. If you will be self-administering, your doctor or nurse will provide guidance 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.
Check the solution before use. Do not use if it is cloudy, leaking, or contains particles. The solution should be colorless to faintly yellow; do not use if the color has changed. Each prefilled syringe or vial is for single use only. Discard any remaining solution after the dose is administered.
Dispose of needles and syringes in a designated sharps disposal container. Do not reuse needles or other items. When the container is full, follow local regulations for disposal. If you have any questions, consult your doctor or pharmacist.
Storage and Handling of Vials
If you draw the medication from a vial into a syringe, it can be stored at room temperature for up to 24 hours.
Storage and Disposal of Your Medication
Store your 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 location, out of the reach of children and pets.
Missing a Dose
If you take this medication on a regular schedule, take the missed dose 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 take extra doses.
If you take this medication as needed, do not take it more frequently than directed by your doctor.
To ensure you get the most out of your medication, follow your doctor's instructions carefully. Read all the information provided to you and follow the instructions closely.
Administration of Injection Products
This medication is administered via injection into the fatty tissue of the skin, typically on the top of the thigh or in the belly area. If someone else is administering the injection, it may be given in the outer area of the upper arm. If you will be self-administering, your doctor or nurse will provide guidance 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.
Check the solution before use. Do not use if it is cloudy, leaking, or contains particles. The solution should be colorless to faintly yellow; do not use if the color has changed. Each prefilled syringe or vial is for single use only. Discard any remaining solution after the dose is administered.
Dispose of needles and syringes in a designated sharps disposal container. Do not reuse needles or other items. When the container is full, follow local regulations for disposal. If you have any questions, consult your doctor or pharmacist.
Storage and Handling of Vials
If you draw the medication from a vial into a syringe, it can be stored at room temperature for up to 24 hours.
Storage and Disposal of Your Medication
Store your 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 location, out of the reach of children and pets.
Missing a Dose
If you take this medication on a regular schedule, take the missed dose 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 take 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 tolerated and appropriate.
- Engage in regular physical activity as tolerated.
- Follow proper injection technique as instructed by your healthcare provider.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
12 mg subcutaneously once daily
Dose Range:
12 - 12 mg
Condition-Specific Dosing:
opioid-induced constipation in patients with chronic non-cancer pain:
12 mg subcutaneously once daily
opioid-induced constipation in patients with advanced illness:
8 mg or 12 mg subcutaneously every other day, based on weight (8 mg for patients weighing <62 kg, 12 mg for patients weighing âĨ62 kg)
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established
Child:
Not established
Adolescent:
Not established
Dose Adjustments
Renal Impairment:
Mild:
No adjustment needed (CrCl 60-90 mL/min)
Moderate:
8 mg subcutaneously once daily (CrCl 30-60 mL/min)
Severe:
8 mg subcutaneously once daily (CrCl <30 mL/min)
Dialysis:
8 mg subcutaneously once daily; administer after dialysis on dialysis days
Hepatic Impairment:
Mild:
No adjustment needed
Moderate:
No adjustment needed
Severe:
Not studied; use with caution
Pharmacology
Mechanism of Action
Methylnaltrexone is a selective, peripherally acting mu-opioid receptor antagonist. It antagonizes the gastrointestinal effects of opioids, such as decreased motility and increased fluid absorption, without reversing central opioid analgesia or precipitating opioid withdrawal symptoms because it does not readily cross the blood-brain barrier.
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 (subcutaneous)
Clearance:
Not available
ExcretionRoute:
Renal (60-70% unchanged), fecal (10-20%)
Unchanged:
60-70% (in urine)
Pharmacodynamics
OnsetOfAction:
Within 30-60 minutes (for bowel movement)
PeakEffect:
Not precisely defined for bowel movement, but peak plasma concentrations occur within 0.5-1.5 hours.
DurationOfAction:
Variable, typically sufficient for once-daily dosing to induce a bowel movement within 4 hours for many patients.
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 upset stomach or vomiting
Black, tarry, or bloody stools
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although 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, contact your doctor for guidance:
Stomach pain
Upset stomach or vomiting
Excessive sweating
Gas
Dizziness
Flushing
* 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 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.
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 upset stomach or vomiting
Black, tarry, or bloody stools
Other Possible Side Effects
Like all medications, this drug can cause side effects. Although 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, contact your doctor for guidance:
Stomach pain
Upset stomach or vomiting
Excessive sweating
Gas
Dizziness
Flushing
* 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 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:
- New, severe, or persistent abdominal pain
- Abdominal distention
- Fever
- Chills
- Nausea or vomiting that is severe or persistent
- Any signs of an allergic reaction (e.g., rash, itching, swelling, severe dizziness, trouble breathing)
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. 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. They will help determine if it is safe to take this medication with your other medications and health conditions. 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. 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. They will help determine if it is safe to take this medication with your other medications and health conditions. 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 have been reported with this drug. Be aware of the following symptoms of opioid withdrawal, and seek medical attention immediately if you experience sweating, chills, diarrhea, stomach pain, anxiety, irritability, or excessive yawning.
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. In such cases, your doctor will need to monitor the unborn baby 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 have been reported with this drug. Be aware of the following symptoms of opioid withdrawal, and seek medical attention immediately if you experience sweating, chills, diarrhea, stomach pain, anxiety, irritability, or excessive yawning.
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. In such cases, your doctor will need to monitor the unborn baby after the medication is administered.
Overdose Information
Overdose Symptoms:
- Exaggerated pharmacologic effects (e.g., diarrhea, abdominal cramping)
- No specific antidote for methylnaltrexone overdose.
What to Do:
Supportive care and symptomatic treatment. Contact a poison control center immediately (Call 1-800-222-1222 in the US).
Drug Interactions
Monitoring
Baseline Monitoring
Diagnosis of Opioid-Induced Constipation (OIC)
Rationale: Confirm appropriate indication for therapy.
Timing: Prior to initiation
Renal function (CrCl)
Rationale: To determine appropriate dosing in patients with renal impairment.
Timing: Prior to initiation
Presence of gastrointestinal lesions or conditions
Rationale: To identify contraindications or increased risk of GI perforation (e.g., severe or worsening abdominal pain, persistent nausea/vomiting, unexplained fever, or signs of acute abdomen).
Timing: Prior to initiation
Routine Monitoring
Bowel movement frequency and consistency
Frequency: Daily
Target: Regular, soft bowel movements
Action Threshold: Lack of response after several days, or worsening constipation
Abdominal pain/discomfort
Frequency: Daily
Target: Absence or mild
Action Threshold: New, severe, or persistent abdominal pain; signs of acute abdomen
Signs/symptoms of GI perforation
Frequency: Daily
Target: Absence
Action Threshold: Severe abdominal pain, distention, fever, chills, nausea, vomiting
Symptom Monitoring
- Abdominal pain (new, severe, or persistent)
- Abdominal distention
- Nausea
- Vomiting
- Fever
- Chills
- Signs of acute abdomen (e.g., guarding, rigidity)
Special Patient Groups
Pregnancy
Limited human data on methylnaltrexone use in pregnant women. Animal studies have shown some evidence of developmental toxicity at high doses. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus.
Trimester-Specific Risks:
First Trimester:
Limited data; animal studies suggest potential for skeletal abnormalities at high doses.
Second Trimester:
Limited data.
Third Trimester:
Limited data; theoretical risk of opioid withdrawal in the neonate if the mother is opioid-dependent, though methylnaltrexone has limited CNS penetration.
Lactation
It is unknown if methylnaltrexone is excreted in human milk. Due to the potential for serious adverse reactions in breastfed infants, including opioid withdrawal, 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:
Unknown; theoretical risk of opioid withdrawal in opioid-dependent infants. Low oral bioavailability in infants may limit systemic exposure.
Pediatric Use
Safety and effectiveness have not been established in pediatric patients. Not recommended for use in this population.
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 and should not be used for other types of constipation.
- Patients should discontinue other laxatives prior to initiating Relistor, then reintroduce them as needed if response to Relistor is inadequate.
- Administer subcutaneously in the thigh, abdomen, or upper arm. Rotate injection sites.
- Monitor patients for severe or persistent abdominal pain, which could indicate GI perforation, a rare but serious adverse event.
- Relistor does not reverse central opioid analgesia, so patients should continue their opioid pain medication as prescribed.
Alternative Therapies
- Naloxegol (Movantik)
- Naldemedine (Symproic)
- Lubiprostone (Amitiza)
- Linaclotide (Linzess)
- Prucalopride (Motegrity)
- Osmotic laxatives (e.g., polyethylene glycol, lactulose)
- Stimulant laxatives (e.g., senna, bisacodyl)
Cost & Coverage
Average Cost:
$1000 - $1500+ per 30 pre-filled syringes (12mg/0.6ml)
Insurance Coverage:
Tier 3 (Non-preferred brand) or Specialty Tier, often requiring prior authorization due to high cost and specific indication.
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe use, never share your medication with others or take someone else's medication. This medication is accompanied by a Medication Guide, which is a crucial patient fact sheet. Please read it carefully and review it again whenever you receive a refill. If you have any questions or concerns about this medication, consult 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. Be prepared to provide detailed information about the overdose, including the substance taken, the amount, and the time it occurred.