Drug reference

nirsevimab

Anti-RSV F-protein monoclonal antibody (passive immunoprophylaxis)

START

Single IM dose at entry to RSV season: 50 mg (<5 kg) or 100 mg (≥5 kg)

TYPICAL MAX

200 mg per RSV season (high-risk 2nd season)

STOP IF

Severe hypersensitivity to first dose

WATCH

Single-dose use; coverage ~5 months (one RSV season)

CDSCO approvedATC J06BD08

Dose laddermg/d

Renal dose adjustmenteGFR mL/min/1.73m²

KDIGO 2024 + manufacturer label

Pharmacokineticsplasma · t hours

ONSET: 12h · IM absorption
PEAK: 6d · Tmax ~6 d
t½: 10.1w · t½ ~71 d
DURATION: 21.4w · seasonal

EXCRETION

Proteolytic catabolism; not excreted intact

route + CYP

INTERACTIONS

—

none in our sources

PREGNANCY

Not applicable (paediatric indication).

FDA category + note

Mechanism

Recombinant human IgG1κ monoclonal antibody binding the prefusion conformation of the RSV fusion (F) protein, blocking viral entry; engineered Fc (YTE) substitutions extend serum half-life for single-dose seasonal protection.

Indications

Prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in neonates / infants entering their first RSV season; high-risk children up to 24 months entering their 2nd RSV season

Dosing

Adult: Not indicated.
Pediatric: Body-weight based single IM dose: <5 kg: 50 mg; ≥5 kg: 100 mg. High-risk children entering 2nd RSV season: 200 mg (two 100 mg IM injections).
Renal adjustment: No adjustment.
Hepatic adjustment: No adjustment.
Geriatric: Not applicable.
Max dose: 200 mg per RSV season (high-risk 2nd season)

Pharmacokinetics

Onset

Neutralising titres immediate (post-IM)

Peak effect

~6 days (Tmax serum)

Duration

~5 months (single seasonal dose)

Half-life

~71 days (engineered YTE Fc-extended)

Bioavailability

IM ~84%

Protein binding

Not applicable

Metabolism

Proteolytic catabolism

Excretion

Catabolised; not excreted intact

Contraindications

History of severe hypersensitivity to nirsevimab or excipients
Caution: clinically significant bleeding disorders or thrombocytopenia (IM injection)

Side effects

Common

Injection-site reactionsRashPyrexia

Serious

Severe hypersensitivity / anaphylaxis (rare)
Apnoea in extremely premature infants (theoretical, low absolute risk)

Pregnancy & lactation

Pregnancy

Not applicable (paediatric indication).

Lactation

Not applicable.

Drug interactions

Im Injections

Moderate

Database

Bleeding/haematoma at site

Caution / firm pressure if bleeding disorder