OPVEE vs RELISTOR

Independent side-by-side comparison.

Rated against independent regulatory sources·Last updated June 7, 2026·How we rate

Possible drug interaction. OPVEE and RELISTOR are different prescription medicines. Combining or switching between them can cause interactions — talk to a pharmacist or prescriber before making changes. This page is not medical advice.

Attribute	OPVEE	RELISTOR
Rating	New	New
Pharmacy pays	—	—
Type	RX	RX
Active ingredient	NALMEFENE HYDROCHLORIDE	METHYLNALTREXONE BROMIDE
Manufacturer	Indivior	Salix
Dosage forms	Spray/Inhaler	Injectable, Tablet
Drug class	Opioid Antagonist	Opioid Antagonist
Boxed warning	None	None
Treats	Opioid-Related Disorders, Respiration Disorders, Drug Overdose	Constipation

opvee relistor

Rating

New

Pharmacy pays

—

Type

Active ingredient

NALMEFENE HYDROCHLORIDE

METHYLNALTREXONE BROMIDE

Manufacturer

Indivior

Salix

Dosage forms

Spray/Inhaler

Injectable, Tablet

Drug class

Opioid Antagonist

Boxed warning

None

Treats

Opioid-Related Disorders, Respiration Disorders, Drug Overdose

Constipation

Frequently asked questions

What is the difference between Opvee and Relistor?

Opvee contains Nalmefene Hydrochloride, while Relistor contains Methylnaltrexone Bromide — they have different active ingredients.

Ratings are based on FDA regulatory (recall-safety) data. This comparison is for general reference only — not medical advice. Always consult a licensed professional before choosing or switching a medication.