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Methylnaltrexone Bromide

Also known as: Relistor

Route: Oral, Subcutaneous

Check Methylnaltrexone Bromide Interactions →

2 interactions on record

Methylnaltrexone Bromide has 2 known drug interactions based on U.S. FDA drug labeling data. 1 are classified as major interactions requiring close medical supervision. Notable interactions include combinations with Other Anticholinergic Agents. Patients taking Methylnaltrexone Bromide should inform their healthcare provider of all current medications — including over-the-counter drugs and supplements — to avoid potentially harmful combinations. Data sourced from OpenFDA and the NIH National Library of Medicine.

Total: 2
Major: 1
Minor: 1

Major (1)

Methylnaltrexone Bromide + Other Anticholinergic Agents— Avoid concomitant use due to potential additive effects of opioid receptor antagonism and increased risk of opioid withd…

Minor (1)

Methylnaltrexone Bromide + Dextromethorphan— Subcutaneous methylnaltrexone did not significantly affect dextromethorphan metabolism in healthy subjects.

Methylnaltrexone Bromide + Other Anticholinergic Agents⚠️Major

Avoid concomitant use due to potential additive effects of opioid receptor antagonism and increased risk of opioid withdrawal.

Methylnaltrexone Bromide + Dextromethorphan🟢Minor

Subcutaneous methylnaltrexone did not significantly affect dextromethorphan metabolism in healthy subjects.

Contraindications

4 CONTRAINDICATIONS RELISTOR is contraindicated in patients with known or suspected gastrointestinal obstruction and patients at increased risk of recurrent obstruction, due to the potential for gastrointestinal perforation [see Warnings and Precautions ( 5.1 )] . Patients with known or suspected mechanical gastrointestinal obstruction and at increased risk of recurrent obstruction. ( 4 , 5.1 )

Pregnancy & Breastfeeding

8.1 Pregnancy Risk Summary The limited available data with RELISTOR in pregnant women are not sufficient to inform a drug-associated risk for major birth defects and miscarriages. There are clinical considerations when RELISTOR is used by pregnant women [see Clinical Considerations]. In animal reproduction studies, no effects on embryofetal development were observed with the administration of intravenous methylnaltrexone bromide during organogenesis in rats and rabbits at doses up to 20 times and 26 times, respectively, the subcutaneous maximum recommended human dose (MRHD) of 12 mg RELISTOR injection per day. The intravenous doses in rats and rabbits are about 0.5 times and 0.7 times, respectively, the oral MRHD of 450 mg/day [see Data]. Advise pregnant women of the potential risk to a fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. Clinical Considerations Fetal/Neonatal Adverse Reactions The use of RELISTOR during pregnancy may precipitate opioid withdrawal in a fetus due to the immature fetal blood-brain barrier. Data Animal Data Reproduction studies have been performed with methylnaltrexone bromide administered during the period of organogenesis to rats at intravenous doses up to 25 mg/kg/day (about 20 times the subcutaneous MRHD of 12 mg/day based on body surface area), and did not cause any adverse effects on embryofetal development. In rabbits, intravenous doses of methylnaltrexone bromide up to 16 mg/kg/day (about 26 times the subcutaneous MRHD of 12 mg/day) did not show any embryofetal toxicity. The intravenous doses in rats (25 mg/kg/day) and rabbits (16 mg/kg/day) are about 0.5 and 0.7 times, respectively, the oral MRHD of 450 mg/day based on body surface area. A pre- and postnatal development study in rats showe

Data sourced from U.S. FDA drug labeling via openFDA and the NIH National Library of Medicine, supplemented with a small number of well-established interactions from curated clinical references. For informational purposes only. Always consult your pharmacist or physician.