SYNAGIS

Indications

• Prevention of serious lower respiratory tract disease caused by RSV in children at high risk
• Children under 6 months of age with significant congenital heart disease
• Children under 2 years of age with a history of bronchopulmonary dysplasia
• Children under 2 years of age with severe immunocompromising conditions

Dosage

Children: Child 1–23 months: Initially 15 mg/kg, administered as soon as stable after surgery, preferably in the anterolateral thigh, then 15 mg/kg once a month during the RSV season. For details regarding specific dosing in at-risk

Mechanism of action

Palivizumab exerts its antiviral effects by binding to the F (fusion) protein of the respiratory syncytial virus (RSV), preventing the virus from entering and infecting host cells. This neutralization of the virus reduces the likelihood of severe respiratory illness associated with RSV infection.

Pharmacodynamics

Palivizumab's pharmacodynamic effects are manifested through its ability to reduce the incidence of hospitalization due to RSV infections in at-risk pediatric populations. The drug's binding affinity to the RSV F protein allows for effective neutralization of the virus, leading to decreased viral load and improved respiratory outcomes in treated individuals.

Pharmacokinetics

Palivizumab is administered via intramuscular injection, demonstrating a peak serum concentration typically occurring about 5 to 7 days post-administration. It has a half-life of approximately 18 to 20 days, allowing for monthly dosing during RSV season. The distribution of palivizumab is extensive, with its volume of distribution reflecting its binding to RSV-infected cells. The elimination of palivizumab is primarily through proteolytic degradation, and it is not significantly cleared by the kidneys.

Contra-indications

• History of severe allergic reactions to palivizumab or any component of the formulation
• Severe combined immunodeficiency syndrome (SCID) in infants
• Anaphylactic reactions to another humanised monoclonal antibody

Adverse effects

• Apnoea
• Seizure
• Urticaria
• Hypersensitivity reactions

Interactions

• No significant drug interactions are documented, but caution is advised in patients receiving immunosuppressive therapy

Precautions

• Use with caution in infants with moderate to severe acute infections
• Monitor for thrombocytopenia
• Consider the possibility of reduced serum palivizumab concentration after cardiac surgery

Pregnancy

Palivizumab is not recommended during pregnancy due to limited data on safety.

Breast-feeding

It is unknown if palivizumab is excreted in human milk; caution should be exercised.

Storage

Store in a refrigerator (2 to 8 degrees Celsius). Do not freeze. Protect from light.

Formulations

• Synagis 100 mg/1 ml solution for injection (AstraZeneca UK Ltd)