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Generic name: palivizumab

What is Synagis?

Synagis is a prescription medication that is used to help prevent a serious lung disease caused by Respiratory Syncytial Virus (RSV) in children:

  • born prematurely (at or before 35 weeks) and who are 6 months of age or less at the beginning of RSV season,
  • who have a chronic lung condition called bronchopulmonary dysplasia (BPD), that needed medical treatment within the last 6 months, and who are 24 months of age or less at the beginning of RSV season,
  • born with certain types of heart disease and who are 24 months of age or less at the beginning of RSV season.

Synagis contains man-made, disease-fighting proteins called antibodies.

It is not known if Synagis is safe and effective to treat the symptoms of RSV in a child who already has RSV. Synagis is used to help prevent RSV disease.

It is not known if Synagis is safe and effective in children who are older than 24 months of age at the start of dosing.

Who should not take Synagis?

Your child should not receive Synagis if they have ever had a severe allergic reaction to it. See the end of this leaflet for a complete list of ingredients in Synagis.

Signs and symptoms of a severe allergic reaction could include:

  • severe rash, hives, or itching skin
  • swelling of the lips, tongue, or face
  • swelling of the throat, difficulty swallowing
  • difficult, rapid, or irregular breathing
  • bluish color of skin, lips, or under fingernails
  • muscle weakness or floppiness
  • unresponsiveness

What should I tell my healthcare provider before taking Synagis?

Before your child receives Synagis, tell your healthcare provider about all of your child’s medical conditions, including if your child:

  • has ever had a reaction to Synagis.
  • has bleeding or bruising problems. Synagis is given by injection. If your child has a problem with bleeding or bruises easily, an injection could cause a problem.

Tell your child’s healthcare provider about all the medicines your child takes, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

How should I take Synagis?

  • Synagis is given as a monthly injection, usually in the thigh (leg) muscle, by your child’s healthcare provider.
  • Your child’s healthcare provider will give you detailed instructions on when Synagis will be given.
    • “RSV season” is the time of year when RSV infections most commonly happen, usually fall through spring, but it may begin earlier or last longer in certain areas). During this time, when RSV is most active, your child will need to receive Synagis injections. Your healthcare provider can tell you when the RSV season starts in your area.
    • Your child should receive the first Synagis injection before the RSV season starts to help prevent RSV infection. If the season has already started, your child should receive their first Synagis injection as soon as possible to help protect them when exposure to the virus is more likely.
    • Synagis is needed every 28-30 days during the RSV season. Each injection of Synagis helps protect your child from severe RSV disease for about 1 month. Keep all of your child’s appointments with your healthcare provider.
  • If your child misses an injection, talk to your healthcare provider and schedule another injection as soon as possible.
  • Your child may still get severe RSV disease after receiving Synagis. Talk to your healthcare provider about what symptoms to look for. If your child gets a RSV infection, they should continue to receive their scheduled Synagis injections to help prevent severe disease from new RSV infections.
  • If your child has certain types of heart disease and has corrective surgery, your healthcare provider may need to give your child an additional Synagis injection soon after surgery.

What are the possible side effects of Synagis?

Synagis may cause serious side effects including:

  • Severe allergic reactions. Severe allergic reactions may happen after any injection of Synagis, and may be life-threatening or cause death. Call your healthcare provider or get medical help right away if your child has any of the signs or symptoms of a serious allergic reaction. See “Who should not receive Synagis?” for more information.

The most common side effects of Synagis include fever and rash.

These are not all the possible side effects of Synagis.

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

You may also report side effects to MedImmune at 1-877-633-4411.

General information about the safe and effective use of Synagis

Medicines are sometimes prescribed for purposes other than those listed in Patient Information leaflets.

You can ask your pharmacist or healthcare provider for information about Synagis that is written for health professionals.

How should I store Synagis?

  • Synagis should be stored between 2°C and 8°C (36°F and 46°F) in its original container.
  • DO NOT freeze.
  • DO NOT use beyond the expiration date.

What are the ingredients in Synagis?

Active ingredient: palivizumab

Inactive ingredients: chloride, glycine, and histidine

For more information, go to or call 1-877-633-4411.

Source: National Library of Medicine. Last updated May 12, 2017.