Relistor Injection

  • Constipation and bowel cleansers

Relistor Injection Generic Name & Formulations

General Description

Methylnaltrexone bromide 8mg/0.4mL, 12mg/0.6mL; soln for SC inj.

Pharmacological Class

Opioid antagonist (peripheral).

See Also

How Supplied

Tabs—60, 90; Single-use vial (12mg/0.6mL)—1; Prefilled syringes (8mg/0.4mL)—7; Prefilled syringes (12mg/0.6mL)—1, 7

Generic Availability


Relistor Injection Indications


Opioid-induced constipation (OIC) in adults with chronic non-cancer pain, including chronic pain related to prior cancer or its treatment in patients who do not require frequent opioid dosage escalation. OIC in adults with advanced illness or pain caused by active cancer who require opioid dosage escalation for palliative care.

Limitations of Use

Use for >4 months has not been studied in the advanced illness population.

Relistor Injection Dosage and Administration


Give by SC inj in upper arm, abdomen, or thigh; rotate inj sites. Chronic non-cancer pain: Discontinue all maintenance laxatives prior to initiation; may be used if suboptimal methylnaltrexone response after 3 days. Reevaluate if opioid regimen is changed. Give 12mg once daily. Advanced illness: Give once every other day as needed (max 1 dose/24hrs). <38kg or >114kg: 0.15mg/kg. 38–<62kg: 8mg. 62–114kg: 12mg. Moderate or severe renal impairment (CrCl<60mL/min): reduce dose by ½ (see full labeling). Severe hepatic impairment: may consider reducing weight-based dose by ½ (non-cancer pain only). Prefilled syringes: use only for 8mg or 12mg fixed doses.


Not established.

Relistor Injection Contraindications


Known or suspected GI obstruction and at increased risk of recurrent obstruction.

Relistor Injection Boxed Warnings

Not Applicable

Relistor Injection Warnings/Precautions


Discontinue if concurrent opioid pain medication is also discontinued. GI perforation; monitor for severe, persistent, or worsening abdominal pain; discontinue if occurs. Discontinue if severe or persistent diarrhea occurs. Increased risk of opioid withdrawal and/or reduced analgesia in those with blood-brain barrier disruptions; monitor for symptoms. Bowel movement may occur within 30 mins of dosing. Elderly. Pregnancy. Nursing mothers: not recommended.

Relistor Injection Pharmacokinetics

See Literature

Relistor Injection Interactions


Potential additive effects and increased risk of opioid withdrawal with concomitant other opioid antagonists; avoid.

Relistor Injection Adverse Reactions

Adverse Reactions

Abdominal pain, flatulence, nausea, dizziness, diarrhea, headache, abdominal distention, vomiting, hyperhidrosis, anxiety, muscle spasms, rhinorrhea, chills, tremor, hot flush; GI perforation, opioid withdrawal.

Relistor Injection Clinical Trials

See Literature

Relistor Injection Note

Not Applicable

Relistor Injection Patient Counseling

See Literature