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Medically reviewed by Last updated on May 6, 2019.


(pah li VIZ u mab)

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)

Brand Names: U.S.

  • Synagis

Pharmacologic Category

  • Monoclonal Antibody


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


Clearance: Infants and Children <24 months of age without CHD: ~11 mL/day

Half-Life Elimination

Infants and Children <24 months without CHD: 20 days

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.

Dosing: Pediatric

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; 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: 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).

RSV, treatment in patients at high-risk for severe disease: Limited data available: Infants, Children, and Adolescents: IV: 15 mg/kg as a single dose; in most patients, used in combination with ribavirin therapy; in two patients with disease progression, a single repeat dose at 3 to 5 days after the initial dose was reported (Chávez-Bueno, 2007). Dosing based on experience in 85 patients the majority of which are pediatric patients and mostly ≤2 years of age. Reported efficacy results variable, an initial double-blind, placebo-controlled trial (n=17 treatment group; all patients ≤2 years) showed statistically significant decreases in RSV tracheal aspirate concentrations vs placebo (Malley, 1998); in another double-blind, placebo-controlled trial (n=22 treatment group; all patients ≤2 years) a decrease in the days of RSV hospitalization, days of supplemental oxygen, and lower respiratory infection scores were reported relative to placebo (Sáez-Llorens, 2004); in an underpowered, observational study of hematopoietic stem cell patients (n=15; age range: 2 to 60 years) a decrease viral shedding and increased 30 day-survival vs ribavirin monotherapy (83.3% vs ~55%) was reported (Boeckh, 2001).


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). Safety and efficacy have not been established for treatment of RSV disease.

Monitoring Parameters

Monitor for anaphylaxis or acute hypersensitivity reactions.

Pregnancy Considerations

Not for adult use.

Patient Education

• Discuss specific use of drug and side effects with caregiver as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Have caregiver report immediately to prescriber shortness of breath, difficulty breathing, slow breathing, shallow breathing, skin discoloration, muscle weakness, severe dizziness, passing out, bruising, bleeding, or application site irritation (HCAHPS).

• Educate caregiver about signs of a significant reaction (eg, 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. Caregiver should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.