Version July 2025
(For additional information see "Palivizumab: Pediatric drug information")
Note: Palivizumab is recommended only in certain scenarios in which nirsevimab is not available (Ref).
Respiratory syncytial virus (RSV), prevention: Infants and Children ≤24 months: IM: 15 mg/kg once monthly throughout RSV season, with the first dose administered prior to commencement of RSV season; if hospitalized at the start of RSV season, palivizumab should be given 48 to 72 hours before discharge or promptly after discharge. During a typical RSV season, up to 5 monthly doses are recommended (Ref).
Cardiopulmonary bypass patients: IM: Administer a 15 mg/kg dose as soon as possible after cardiopulmonary bypass procedure or at the conclusion of extracorporeal membrane oxygenation, even if <1 month from previous dose. A 58% decrease in palivizumab serum concentrations has been noted after cardiopulmonary bypass (Ref).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Infants and Children ≤24 months: There are no dosage adjustments provided in the manufacturer's labeling.
Infants and Children ≤24 months: There are no dosage adjustments provided in the manufacturer's labeling.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified.
>10%:
Dermatologic: Skin rash (12%)
Miscellaneous: Fever (27%)
1% to 10%: Immunologic: Antibody development (1% to 2%)
<1%, postmarketing, and/or case reports: Anaphylaxis (very rare; includes angioedema, dyspnea, hypotonia, pruritus, respiratory failure, unresponsiveness, urticaria), hypersensitivity reaction, injection site reaction, thrombocytopenia
Significant prior hypersensitivity reaction to palivizumab or any component of the formulation
Canadian labeling: Additional contraindications (not in US labeling): Known hypersensitivity to other humanized monoclonal antibodies.
Concerns related to adverse effects:
• Anaphylactoid/hypersensitivity reactions: Anaphylaxis and anaphylactic shock, some fatal cases, have been reported following initial exposure or re-exposure to palivizumab; other acute hypersensitivity reactions (may be severe), have also been reported. If a significant hypersensitivity reaction occurs, permanently discontinue therapy. If anaphylaxis or other significant hypersensitivity reaction occurs, administer appropriate medications (eg, epinephrine) and provide supportive care as required. If a mild hypersensitivity reaction occurs, clinical judgment should be used regarding cautious readministration.
Disease-related concerns:
• Bleeding disorders: Use with caution in patients with a history of bleeding disorders (including thrombocytopenia); bleeding/hematoma may occur from IM administration.
Other warnings/precautions:
• Appropriate use: Efficacy has not been established for treatment of RSV disease and use is not recommended (AAP 2014; AAP [Caserta 2023]). A large placebo-controlled trial evaluated 413 infants ≤3 months of age (median age: 49 days) admitted to the hospital through an emergency department with RSV+ bronchiolitis; the treatment group (n=208) received a single dose of palivizumab (15 mg/kg IV); there was no difference between groups in readmission in the 3 weeks following hospital discharge, time to readiness for discharge, or transfer to intensive care during admission (Alansari 2019).
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution, Intramuscular [preservative free]:
Synagis: 50 mg/0.5 mL (0.5 mL); 100 mg/mL (1 mL)
No
Solution (Synagis Intramuscular)
50 mg/0.5 mL (per 0.5 mL): $2,184.79
100 mg/mL (per mL): $4,125.50
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Solution, Intramuscular:
Synagis: 50 mg/0.5 mL (0.5 mL); 100 mg/mL (1 mL)
Parenteral: IM: Administer undiluted solution IM, preferably in the anterolateral aspect of the thigh; gluteal muscle should not be used routinely as an injection site because of the risk of damage to the sciatic nerve. Injection volume over 1 mL should be given as a divided dose. Do not dilute product; do not shake or vigorously agitate the vial.
Respiratory syncytial virus prophylaxis: Prevention of serious lower respiratory tract disease caused by respiratory syncytial virus (RSV) in pediatric patients with a history of premature birth (≤35 weeks gestational age) and who are ≤6 months at the beginning of RSV season; pediatric patients with bronchopulmonary dysplasia (BPD) that required medical treatment within the previous 6 months and who are ≤24 months at the beginning of RSV season; or pediatric patients with hemodynamically significant congenital heart disease (CHD) and who are ≤24 months at the beginning of RSV season.
The American Academy of Pediatrics (AAP 2014) recommends RSV prophylaxis with palivizumab during RSV season for:
Infants born at ≤28 weeks 6 days gestational age and <12 months at the start of RSV season
Infants <12 months of age with chronic lung disease (CLD) of prematurity
Infants ≤12 months of age with hemodynamically significant CHD
Infants and children <24 months of age with CLD of prematurity necessitating medical therapy (eg, supplemental oxygen, bronchodilator, diuretic, or chronic steroid therapy) within 6 months prior to the beginning of RSV season
AAP also suggests that palivizumab prophylaxis may be considered in the following circumstances:
Infants <12 months of age with congenital airway abnormality or neuromuscular disorder that decreases the ability to manage airway secretions
Infants <12 months of age with cystic fibrosis with clinical evidence of CLD and/or nutritional compromise
Children <24 months with cystic fibrosis with severe lung disease (previous hospitalization for pulmonary exacerbation in the first year of life or abnormalities on chest radiography or chest computed tomography that persist when stable) or weight for length less than the 10th percentile
Infants and children <24 months who are profoundly immunocompromised
Infants and children <24 months undergoing cardiac transplantation during RSV season
Limitations of use: Safety and efficacy have not been established for treatment of RSV disease.
Synagis may be confused with Synalgos-DC, Synflorix, Synvisc
None known.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Efgartigimod Alfa: May decrease therapeutic effects of Fc Receptor-Binding Agents. Risk C: Monitor
Nipocalimab: May decrease therapeutic effects of Fc Receptor-Binding Agents. Risk C: Monitor
Rozanolixizumab: May decrease therapeutic effects of Fc Receptor-Binding Agents. Risk C: Monitor
Not for adult use.
Not for adult use.
Observe for anaphylactic or severe allergic reactions; respiratory syncytial virus infection.
Exhibits neutralizing and fusion-inhibitory activity against RSV; these activities inhibit RSV replication in laboratory and clinical studies
Bioavailability: Infants and Children ≤24 months without congenital heart disease (CHD): IM: 70%.
Half-life elimination: Infants and Children ≤24 months without CHD: 20 to 24.5 days.
Time to peak, serum: IM: Infants and Children ≤24 months: 3 to 5 days (Resch 2017); palivizumab concentrations sufficient to inhibit respiratory syncytial virus 2 days after administration (Sáez-Llorens 1998).
Excretion: Clearance is similar regardless of gestational age, though interpatient variability is high (48.7% coefficient of variation). Clearance may be slightly increased (~20%) in patients with chronic lung disease of prematurity or in the presence of antipalivizumab antibodies (Robbie 2012).
Pediatric: Trough palivizumab concentrations are similar in pediatric patients with and without congenital heart disease. However, serum concentrations are reduced by an average of 58% following cardiopulmonary bypass (AAP 2014).
