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Generic name: palivizumab systemic

Brand names: Synagis

Dosage Forms

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)


Mechanism of Action

Exhibits neutralizing and fusion-inhibitory activity against RSV; these activities inhibit RSV replication in laboratory and clinical studies



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).

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).

Half-Life Elimination

Infants and Children <24 months without congenital heart disease: 20 to 24.5 days.

Use in Specific Populations

Special Populations: Children

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).

Use: Labeled Indications

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.


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.

Dosage and Administration

Dosing: Pediatric

Note: See Use for description of patients for whom palivizumab prophylaxis may be considered.

Respiratory syncytial virus (RSV), prevention: Infants and Children <24 months: IM: 15 mg/kg once monthly throughout RSV season; 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 (AAP 2014). Note: AAP recommends a maximum 5 doses per season; if hospitalization occurs for breakthrough RSV infection, monthly prophylaxis should be discontinued for the remainder of that season (AAP 2014).

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 (AAP 2014).


Store between 2°C and 8°C (36°F and 46°F) in original container; do not freeze. Extended storage information may be available; contact product manufacturer to obtain current recommendations. Discard unused portion.

Drug Interactions

There are no known significant interactions.

Test Interactions

May interfere (false negatives) with immunological-based RSV diagnostic tests (antigen detection) and viral culture assays; rely on reverse-transcriptase-polymerase chain reaction-based assays and clinical findings.

Adverse Reactions


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


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.

Drug-drug interactions:

  • Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Other warnings/precautions:

  • Appropriate use: Palivizumab is not recommended for the prevention of health care-associated RSV disease (AAP 2014). Efficacy has not been established for treatment of RSV disease and use is not recommended (AAP 2014, AAP 2019 [reaffirmed]). 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).

Monitoring Parameters

Monitor for anaphylaxis or acute hypersensitivity reactions.


Pregnancy Considerations

Not for adult use.

Patient Education

What is this drug used for?

  • It is used to prevent RSV infection.

Other side effects of this drug: Talk with your doctor right away if you have any of these signs of:

  • Shortness of breath
  • Trouble breathing
  • Slow breathing
  • Shallow breathing
  • Skin discoloration
  • Muscle weakness
  • Severe dizziness
  • Passing out
  • Bruising
  • Bleeding
  • Application site irritation
  • Signs of a significant reaction like wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat.

Note: This is not a comprehensive list of all side effects. Talk to your doctor if you have questions.

Consumer Information Use and Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only the healthcare provider has the knowledge and training to decide which medicines are right for a specific patient. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from the healthcare provider. You must talk with the healthcare provider for complete information about the risks and benefits of using this medicine.

Source: Wolters Kluwer Health. Last updated February 3, 2020.