General MedicinePrescription OnlyPregnancy Cat. Not classifiedFDA Yes
Relistor
METHYLNALTREXONE BROMIDE
1 INDICATIONS AND USAGE • RELISTOR is an opioid antagonist. RELISTOR tablets and RELISTOR injection are indicated for the treatment of opioid-induced constipation (OIC) in adults with chronic non-cancer pain, including patients with chronic pain related to prior cancer or its treatment who do not require frequent (e.g., weekly) opioid dosage escalation. ( 1.1 ) • RELISTOR injection is indicated for the treatment of OIC in adults with advanced illness or pain caused by active cancer who require o...
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Brand names:Relistor
Quick Reference
Medicine ClassGeneral Medicine
FDA ApprovedYes
PregnancyCategory Not classified
Quick Facts
- Active ingredient
- METHYLNALTREXONE BROMIDE
- Medicine class
- General Medicine
- Brand names
- Relistor
- Availability
- Prescription only (Rx)
- Pregnancy category
- Not classified
- Half-life
- half-life (t 1/2 ) of approximately 15 hours
- FDA approved
- Yes
What Is Relistor?
1 INDICATIONS AND USAGE • RELISTOR is an opioid antagonist. RELISTOR tablets and RELISTOR injection are indicated for the treatment of opioid-induced constipation (OIC) in adults with chronic non-cancer pain, including patients with chronic pain related to prior cancer or its treatment who do not require frequent (e.g., weekly) opioid dosage escalation. ( 1.1 ) • RELISTOR injection is indicated for the treatment of OIC in adults with advanced illness or pain caused by active cancer who require o...
Relistor (METHYLNALTREXONE BROMIDE) belongs to the General Medicine class of medications. It was first approved by the FDA in Yes. This medication requires a prescription from a licensed healthcare provider.
Key Safety Information
- •Always follow the dose recommended by your healthcare professional. Taking more than prescribed increases the risk of side effects including serious complications.
- •Seek emergency care if you experience signs of an allergic reaction — hives, swelling, difficulty breathing, or rash. Stop the medication and call your doctor immediately.
- •Some medications can increase the risk of cardiovascular events. Tell your doctor if you have high blood pressure, a history of heart attack or stroke, or any pre-existing health condition.
- •Avoid or limit alcohol while taking Relistor. Do not drink alcohol without first discussing it with your healthcare provider as it may increase adverse effects.
- •Take Relistor with food or a full glass of water if stomach upset occurs. Stop use and talk to your doctor if you experience persistent stomach pain or GI symptoms.
- •Tell your doctor about all medications, supplements, and vitamins you take. Some combinations significantly increase the risk of harm.
This is a summary only. Always read the full prescribing information and consult your healthcare provider for personalized medical advice.
Uses & Indications
Relistor is prescribed for the following conditions. Some uses are FDA-approved indications; others may be evidence-based off-label uses. Consult your healthcare provider for personalized guidance.
1 INDICATIONS AND USAGE • RELISTOR is an opioid antagonist.
RELISTOR tablets and RELISTOR injection are indicated for the treatment of opioid-induced constipation (OIC) in adults with chronic non-cancer pain, including patients with chronic pain related to prior cancer or its treatment who do not require frequent (e.g., weekly) opioid dosage escalation.
( 1.1 ) • RELISTOR injection is indicated for the treatment of OIC in adults with advanced illness or pain caused by active cancer who require opioid dosage escalation for palliative care.
( 1.2 ) 1.1 Opioid-Induced Constipation in Adult Patients with Chronic Non-Cancer Pain RELISTOR tablets and RELISTOR injection are indicated for the treatment of opioid-induced constipation (OIC) in adult patients with chronic non-cancer pain, including patients with chronic pain related to prior cancer or its treatment who do not require frequent (e.g., weekly) opioid dosage escalation.
1.2 Opioid-Induced Constipation in Adult Patients with Advanced Illness RELISTOR injection is indicated for the treatment of OIC in adult patients with advanced illness or pain caused by active cancer who require opioid dosage escalation for palliative care.
Dosage Guide
The following are general dosing guidelines only. Your actual dose should be determined by your healthcare provider based on your condition, renal/hepatic function, and other medications.
AD
Adult Dosage
2 DOSAGE AND ADMINISTRATION Administration Instructions ( 2.1 ) • Be within close proximity to toilet facilities once administered. • Discontinue if treatment with opioid pain medication is also discontinued. • In adult patients with chronic non-cancer pain and OIC: o Patients receiving opioids for less than 4 weeks may be less responsive to RELISTOR. o Discontinue all maintenance laxative therapy before starting RELISTOR; may resume laxatives if there is a suboptimal response to RELISTOR after 3 days. o Re-evaluate the continued need for RELISTOR when opioid regimen is changed to avoid adverse reactions. • In patients with chronic non-cancer pain and OIC, take RELISTOR tablets with water on an empty stomach at least 30 minutes before the first meal of the day. Dosing • For OIC in adult patients with chronic non-cancer pain ( 2.2 ): o RELISTOR tablets: The recommended dosage is 450 mg once daily in the morning. o RELISTOR injection: The recommended dosage is 12 mg subcutaneously once d
Available Forms
Available Strengths
Side Effects
Common
- 6 ADVERSE REACTIONS Serious and important adverse reactions described elsewhere in the labeling include: • Gastrointestinal perforation [see Warnings and Precautions ( 5.1 )] • Severe or persistent diarrhea [see Warnings and Precautions ( 5.2 )] • Opioid withdrawal [see Warnings and Precautions ( 5.3 )] The most common adverse reactions are: OIC in adult patients with chronic non-cancer pain ( 6.1 ) • RELISTOR tablets (≥ 2%): abdominal pain, diarrhea, headache, abdominal distention, vomiting, hyperhidrosis, anxiety, muscle spasms, rhinorrhea, and chills.
- • RELISTOR injection (≥ 1%): abdominal pain, nausea, diarrhea, hyperhidrosis, hot flush, tremor, and chills.
- OIC in adult patients with advanced illness ( 6.1 ) • RELISTOR injection (≥ 5%): abdominal pain, flatulence, nausea, dizziness, and diarrhea.
- To report SUSPECTED ADVERSE REACTIONS, contact Salix Pharmaceuticals at 1-800-321-4576 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
- 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.
- Opioid-Induced Constipation in Adult Patients with Chronic Non-Cancer Pain The safety of RELISTOR tablets was evaluated in a double-blind, placebo-controlled trial in adult patients with OIC and chronic non-cancer pain receiving opioid analgesia.
- This study (Study 1) included a 12-week, double-blind, placebo-controlled period in which adult patients were randomized to receive RELISTOR tablets 450 mg orally (200 patients) or placebo (201 patients) [see Clinical Studies ( 14.1 ) ] .
Serious
- 5 WARNINGS AND PRECAUTIONS • Gastrointestinal Perforation : Consider the overall risk benefit in patients with known or suspected lesions of the GI tract.
- Monitor for severe, persistent or worsening abdominal pain;
- discontinue if development of symptoms.
- ( 5.1 ) • Severe or Persistent Diarrhea : Discontinue if severe or persistent diarrhea occurs during treatment.
- ( 5.2 ) • Opioid Withdrawal : Consider the overall risk benefit in patients with disruptions to the blood-brain barrier.
Rare
Medicine Interactions
Always inform your healthcare provider and pharmacist about ALL medications you take, including prescriptions, OTC medicines, vitamins, and supplements.
MajorModerateMinor
Warnings & Contraindications
5 WARNINGS AND PRECAUTIONS • Gastrointestinal Perforation : Consider the overall risk benefit in patients with known or suspected lesions of the GI tract. Monitor for severe, persistent or worsening abdominal pain; discontinue if development of symptoms. ( 5.1 ) • Severe or Persistent Diarrhea : Discontinue if severe or persistent diarrhea occurs during treatment. ( 5.2 ) • Opioid Withdrawal : Con
5.1 Gastrointestinal Perforation Cases of gastrointestinal perforation have been reported in adult patients with OIC and advanced illness with conditions that may be associated with localized or diffuse reduction of structural integrity in the wall of the gastrointestinal tract (e.g., peptic ulcer disease, Ogilvie’s syndrome, diverticular disease, infiltrative gastrointestinal tract malignancies o
5.2 Severe or Persistent Diarrhea If severe or persistent diarrhea occurs during treatment, advise patients to discontinue therapy with RELISTOR and consult their healthcare provider.
How Relistor Works
12.1 Mechanism of Action Methylnaltrexone is a selective antagonist of opioid binding at the mu-opioid receptor. As a quaternary amine, the ability of methylnaltrexone to cross the blood-brain barrier is restricted. This allows methylnaltrexone to function as a peripherally-acting mu-opioid receptor antagonist in tissues such as the gastrointestinal tract, thereby decreasing the constipating effects of opioids without impacting opioid-mediated analgesic effects on the central nervous system (CNS).
Pharmacokinetics
Absorption
Absorption Tablets Following administration of a single 450 mg dose of RELISTOR tablets in OIC patients or healthy subjects, peak concentrations (C max ) of methylnaltrexone were observed at approximately 1
Half-Life
half-life (t 1/2 ) of approximately 15 hours
Metabolism
Metabolism In an intravenous mass balance study, approximately 44% of the administered radioactivity was recovered in the urine over 24 hours with 5 distinct metabolites
Excretion
Excretion In an intravenous mass balance study, approximately half of the dose was excreted in the urine (54%), and 17% of administered dose was excreted in the feces up to 168 hours postdose
Pregnancy & Breastfeeding Safety
Not classified
Breastfeeding
Many medications pass into breast milk in varying amounts. Before using Relistorwhile breastfeeding, discuss the benefits and risks with your healthcare provider or pharmacist — they can weigh your dose, your infant's age, and available lactation safety data to find the safest option for you and your baby.
Storage & Handling
Store at room temperature. Keep away from moisture and heat. Keep out of reach of children.
Frequently Asked Questions
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Complete adverse effect profile including common, serious, and rare reactions
Sources & References
- • FDA Prescribing Information — Official labeling and package insert for Relistor
- • U.S. National Library of Medicine — MedlinePlus drug information
- • American Hospital Formulary Service (AHFS) — Clinical pharmacology monograph
- • PubMed / MEDLINE — View clinical studies
Last reviewed by MedCentralHub Medical Review Board · MedCentralHub Editorial Policy
Medical Disclaimer
The information on this page is for educational purposes only and is not intended as medical advice, diagnosis, or treatment. Always consult your doctor, pharmacist, or qualified healthcare provider before starting, stopping, or changing any medication.