Methylnaltrexone Bromide

Treats opioid-induced constipation (OIC). Sold as Relistor. Every FDA application for this active ingredient: 2 branded and 3 generic.

As of Nov 15, 2026, FDA lists 5 applications for Methylnaltrexone Bromide (sold as Relistor), first approved Apr 24, 2008, with 1 new use approved and 0 published complete response letters.

First approved: Apr 24, 2008
Applications: 5
New uses approved: 1
Complete response letters: 0
Medicare spending, 2025: $142M
First approved in the EU: Jul 1, 2008

Medicare Spending

CMS Part D and Part B, 2025, before manufacturer rebates; matched by generic name

Product	Part	Spending, 2025	Change	Beneficiaries
Relistor	Part D	$142M	+6%	14,919

Orphan Designations (FDA)

One designation, 0 approved for the designated use; see all orphan designations

Treatment of chronic opioid-induced constipation unresponsive to conventional therapy.Progenics Pharmaceuticals, Inc. · designated Jun 17, 1996

Approvals in the EU (EMA)

First approved in the EU 2 months after the US. Centrally authorised medicines, matched by ingredient; see all EU approvals

Relistor, new substanceBausch Health Ireland Limited · Jul 1, 2008

Clinical Trials

2 open or ongoing studies name this ingredient as an intervention, including as a comparator; newest first. See all


Methylnatrexone In Resectable Head and Neck Squamous Cell Carcinoma (MINK). A "Window of Opportunity" Pilot Study.Head and Neck Squamous Cell Carcinoma · M.D. Anderson Cancer Center	Phase 4	Recruiting	Dec 8, 2023
Chronic Widespread Pain in HIV: Novel Mechanisms and TherapeuticsChronic Widespread Pain · Florida International University	Not applicable	Recruiting	Mar 9, 2021

Applications

NDAs, BLAs and generic ANDAs for this ingredient, oldest first; each opens its full history


Apr 24, 2008	RelistorNDA 21964 · New molecular entity	Salix Pharms	12	Marketed
Jul 19, 2016	RelistorNDA 208271 · New dosage form	Salix	3	Marketed
Aug 26, 2024	Methylnaltrexone BromideANDA 208112	Actavis LLC	0	Discontinued
May 28, 2025	Methylnaltrexone BromideANDA 208592	Mylan Labs Ltd	0	Discontinued
—	Methylnaltrexone BromideANDA 208038	US Generics, Steriles	0	Discontinued

Applications, approvals and products come from FDA's Drugs@FDA data files, refreshed weekly, grouped by active ingredient as FDA spells it. Complete response letters are FDA's published letters. Medicare spending is CMS's Part D and Part B dashboard, matched to this ingredient by generic name; shortages are FDA's shortage list, matched by application number; clinical trials are ClinicalTrials.gov studies naming the ingredient as an intervention, refreshed daily; safety programs are FDA's REMS list, matched by application number or, for shared programs, by ingredient. Drugs@FDA