Nirsevimab

BEYFORTUS

Open Nirsevimab in the interactive console ↗

Pronunciation: nir-SEV-i-mab (bay-FOR-tus)

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

What it isLong-acting anti-RSV antibody; passive immunization of infants.

Why this oneA single dose covers an entire RSV season.

What limits itHypersensitivity and injection-site reactions can occur; it prevents RSV disease but does not treat an active infection.

Nirsevimab molecular structure (skeletal formula) — Molecular structure: Nirsevimab

FDA label

Read the full label on DailyMed ↗

FDA dosing	Population	Start	Target	Max
Prevention of RSV lower respiratory tract disease — first RSV season	Neonates and infants	50 mg IM if <5 kg; 100 mg IM if ≥5 kg	single IM dose	100 mg (single dose)
Prevention of RSV lower respiratory tract disease — second RSV season (children who remain at increased risk)	Children up to 24 months	200 mg IM (2 × 100 mg)	single dosing	200 mg

Renal Undefined

Hepatic Undefined

Additional dose recommended after cardiac surgery with cardiopulmonary bypass once the child is stable

Instructions

Administer as an intramuscular injection, preferably in the anterolateral thigh (avoid gluteal muscle)
May be given concomitantly with childhood vaccines using separate syringes at different sites
Give with caution in thrombocytopenia, coagulation disorders, or anticoagulation therapy
Do not mix with vaccines or other medications in the same syringe

Available strengths

inj 100 mg/mL

Cautions

Serious hypersensitivity reactions including anaphylaxis (urticaria, dyspnea, cyanosis, hypotonia) — initiate appropriate treatment
Use with caution in individuals with clinically significant bleeding disorders (IM injection)

Adverse reactions

Rash
Injection site reactions

Pregnancy Not indicated for use in females of reproductive potential

Lactation Not indicated for use in females of reproductive potential

Cost

Nirsevimab (BEYFORTUS)

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

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

NO BOXED WARNINGS

Principal riskProphylaxis only; supply constrained

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

Legacy pregnancy categoryN/A (post-2015 labeling)

Defining liabilityHypersensitivity following intramuscular RSV prophylaxis

Open Nirsevimab in the interactive console ↗