Nalmefene nasal

OPVEE

Open Nalmefene nasal in the interactive console ↗

Pronunciation: NAL-me-feen

Nalmefene nasal ballicule: receptor binding, kinetics and half-life diagram — Mechanism of action: Nalmefene nasal ballicule

Nalmefene nasal Opvee mascot mnemonic cartoon — Visual mnemonic: Nalmefene nasal mascot
**“Nail my fingers (to Open V)”**

What it isLong-acting opioid receptor antagonist used intranasally for emergency reversal of known or suspected opioid overdose.

Why this oneIts duration is longer than naloxone’s and may better match long-acting or high-potency synthetic opioids.

What limits itIt can precipitate severe, prolonged withdrawal and does not replace ventilation, repeat dosing, surveillance, or emergency care.

Pearls

Half-life about 11 hours, far longer than naloxone.
Prescription-only, unlike OTC naloxone nasal spray.
Pregnancy: no human data; animal studies reassuring.

Nalmefene nasal molecular structure (skeletal formula) — Molecular structure: Nalmefene nasal

FDA-approved for

opioid overdose (1995)
alcohol use disorder (EU)

Principal risksevere, prolonged precipitated opioid withdrawal

Classes and tags

Clinical profile

Therapeutic safety burden1 / 4

Overdose danger1 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk2 / 4

Legacy pregnancy categoryC

Defining liabilityUsually well tolerated; abrupt opioid withdrawal can be severe and prolonged.

FDA label

Read the full label on DailyMed ↗

NO BOXED WARNINGS

Dosing under review against the product label.

Available strengths

inj 0.1, 1 mg/mL
sol 1.5 mg/0.5 mL
sol 2 mg/2 mL
sol 0.1 mg/mL
nasal spray 2.7 mg/spray

Cautions

Recurrent respiratory/CNS depression — keep under surveillance
Limited efficacy vs partial/mixed opioid agonists (e.g., buprenorphine); repeat doses may be needed
May precipitate severe opioid withdrawal (life-threatening in neonates)
Abrupt reversal may cause adverse cardiovascular effects (esp. preexisting CV disease)
Attempts to overcome the blockade with opioids can cause intoxication and death

Adverse reactions

Feeling hot
Nausea
Headache
Dizziness
Chills
Vomiting
Allodynia
Palpitations
Tinnitus

Pregnancy No human data; do not withhold for opioid overdose; no embryo-fetal harm in animals

Lactation No human data; present in rat milk

Cost

Nalmefene nasal (OPVEE)

Strength		#/mo	generic $/unit	CostPlus
0.1 mg/mL	inj	per unit		not offered
1 mg/mL	inj	per unit		not offered

NADAC is a voluntary CMS survey of what retail community pharmacies pay for the drugs they stock. Nalmefene nasal is administered under clinical supervision and dispensed outside retail pharmacies, so it rarely appears on surveyed invoices.

Generic entryBy 2023

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Memory aids: interaction avatars

no kinetic interactions

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Self-check

How does nalmefene duration compare with naloxone’s?
Longer.
What withdrawal problem can nalmefene precipitate?
Severe, prolonged withdrawal.