Synagis Side Effects

Generic name: palivizumab

Medically reviewed by Drugs.com. Last updated on Apr 20, 2025.

Note: This document provides detailed information about Synagis.

Applies to palivizumab: intramuscular solution Side Effects associated with palivizumab. Some dosage forms listed on this page may not apply specifically to the brand name Synagis.

Applies to palivizumab: intramuscular solution.

Precautions

It is very important that your doctor check your child's progress at regular visits. This will allow your child's doctor to see if the medicine is working properly and to decide if your child should continue to use it.

This medicine may cause serious types of allergic reactions, including anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Call your doctor right away if your child has a rash, itching, hoarseness, lightheadedness, dizziness, or fainting, trouble breathing, trouble swallowing, or any swelling of the hands, face, or mouth after receiving the medicine.

If your child has certain types of heart disease and needs to have a corrective surgery, your doctor may need to give your child an additional shot of this medicine soon after surgery.

Make sure any doctor or dentist who treats your child knows that he or she is using this medicine. This medicine may affect the results of certain medical tests.

Serious side effects of Synagis

Along with its needed effects, palivizumab (the active ingredient contained in Synagis) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking palivizumab:

Other side effects of Synagis

Some side effects of palivizumab may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

For healthcare professionals

Applies to palivizumab: intramuscular powder for injection, intramuscular solution.

General adverse events

The most serious adverse reactions are anaphylaxis and other acute hypersensitivity reactions.^[Ref]

Gastrointestinal

• Common (1% to 10%): Nausea, vomiting, diarrhea^[Ref]

Hypersensitivity

• Frequency not reported: Anaphylaxis, anaphylactic shock (sometimes fatal)
• Postmarketing reports: Angioedema^[Ref]

Local

• Common (1% to 10%): Injection site reactions^[Ref]

Other

• Very common (10% or more): Pyrexia^[Ref]

Dermatologic

• Very common (10% or more): Rash
• Uncommon (0.1% to 1%): Urticaria
• Frequency not reported: Pruritus^[Ref]

Cardiovascular

• Frequency not reported: Arrhythmia (during studies of congenital heart disease patients)^[Ref]

Hematologic

• Uncommon (0.1% to 1%): Thrombocytopenia (mild), eosinophilia (mild)
• Postmarketing reports: Severe thrombocytopenia (platelet count less than 50,000/microliter)^[Ref]

Nervous system

• Uncommon (0.1% to 1%): Convulsions^[Ref]

Respiratory

• Frequency not reported: Cyanosis during studies of congenital heart disease patients
• Postmarketing reports: Dyspnea, asthma, bronchospasm^[Ref]

See also:

Frequently asked questions

• What are the symptoms of RSV (respiratory syncytial virus)?

Further information

Synagis side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer