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Generic name: palivizumabPAL-i-VIZ-oo-mab ]
Drug class: Immune globulins

Medically reviewed by Last updated on Dec 27, 2022.

What is Synagis?

Synagis is a man-made antibody to respiratory syncytial virus (RSV). RSV can cause serious illness in children. Palivizumab helps keep RSV cells from multiplying in the body.

Synagis is used to prevent serious lung disease caused by respiratory syncytial virus in premature infants, and infants born with certain lung disorders or heart disease.

Synagis works best in children who are 24 months old or younger at the beginning of RSV season (6 months or younger for premature infants). It will not treat a child who is already sick with RSV disease.


Synagis should not be given to a child who has had a severe allergic reaction to palivizumab.

Before your child receives the injection, tell your doctor if the child has a bleeding or blood-clotting disorder; or a low level of platelets in the blood.

Call your doctor at once if your child has a serious side effect after receiving this medicine, such as high fever, ear pain or drainage, warmth or swelling of the ear; crying or fussiness, change in appetite or sleeping patterns, easy bruising or bleeding, or trouble breathing.

Before taking this medicine

Synagis should not be given to a child who has had a severe allergic reaction to palivizumab.

To make sure Synagis is safe for your child, tell your doctor if the child has ever had:

  • a bleeding or blood clotting disorder; or

  • low levels of platelets in the blood.

How is Synagis given?

Synagis is injected into a muscle. A healthcare provider will give your child this injection.

Synagis is given once a month during the RSV season, which is usually November through April but may be different where you live.

To best help prevent RSV infection, your child's first injection should be given before RSV season begins.

During RSV season, your child should receive a Synagis injection once every 28 to 30 days. Each injection can help protect your child from RSV for about 1 month.

Be sure to keep all appointments for your child's injections. Even if your child gets sick with RSV disease, the child should continue to receive all scheduled Synagis injections.

This medicine can cause unusual results with certain medical tests. Tell any doctor who treats you that you are using this medicine.

What happens if I miss a dose?

Call your doctor for instructions if you miss an appointment for your child's injection.

What happens if I overdose?

Since this medication is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

What should I avoid while receiving Synagis?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Synagis side effects

Get emergency medical help if your child has signs of an allergic reactionto Synagis: hives, severe rash, itching; rapid or difficult breathing; blue-colored lips, skin, or fingernails; muscle weakness, being hard to wake up; swelling of the face, lips, tongue, or throat.

Common Synagis side effects may include:

  • fever; or

  • rash.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Dosing information

Usual Pediatric Dose for Respiratory Syncytial Virus:

Pediatric patients 24 months of age or less:
15 mg/kg IM once a month during RSV season (the first dose should be administered prior to commencement of the RSV season and the remaining doses should be administered monthly throughout the RSV season)

-Children who develop an RSV infection should continue to receive monthly doses throughout the RSV season.
-In the northern hemisphere, the RSV season typically commences in November and lasts through April, but it may begin earlier or persist later in certain communities.
-Serum levels of this drug are decreased after cardiopulmonary bypass. Children undergoing cardiopulmonary bypass should receive an additional dose as soon as possible after the cardiopulmonary bypass procedure (even if sooner than a month from the previous dose). Thereafter, doses should be administered monthly as scheduled.

Use: For the prevention of serious lower respiratory tract disease caused by respiratory syncytial virus (RSV) in children at high risk of RSV disease. The following points should be considered when prescribing this drug:
-Safety and efficacy were established in children with bronchopulmonary dysplasia (BPD), infants with a history of premature birth (less than or equal to 35 weeks gestational age), and children with hemodynamically significant congenital heart disease (CHD).
-Safety and efficacy have not been established for treatment of RSV disease.

What other drugs will affect Synagis?

Other drugs may interact with palivizumab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Where can I get more information?

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use Synagis only for the indication prescribed.

Further information

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