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Synagis Side Effects Center
Medical Editor: John P. Cunha, DO, FACOEP
Synagis (palivizumab) is used to prevent serious lung disease caused by respiratory syncytial virus (RSV) in premature infants, and infants born with certain lung disorders or heart disease. It will not treat a child who is already sick with RSV disease. Synagis is a man-made antibody to RSV. Common side effects include diarrhea, fever, cough, earache, runny nose, or pain/redness/swelling at the injection site.
The recommended dose of Synagis is 15 mg per kg of body weight given monthly by intramuscular injection. The first dose of Synagis should be administered prior to commencement of the RSV season and the remaining doses should be administered monthly throughout the RSV season. There may be other drugs that can interact with Synagis. Tell your doctor about all the prescription and over-the-counter medications your child has received. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your child's doctor. Synagis is not indicated for adult usage. It is not known whether Synagis can cause fetal harm or could affect reproductive capacity when administered to a pregnant woman. Because this drug is not for adult use, it is not recommended while breast-feeding.
Our Synagis (palivizumab) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
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.
What is Patient Information in Detail?
Easy-to-read and understand detailed drug information and pill images for the patient or caregiver from Cerner Multum.
Synagis in Detail - Patient Information: Side Effects
Get emergency medical help if your child has any of these signs of an allergic reaction: hives; difficult breathing; swelling of the face, lips, tongue, or throat.
Call your doctor at once if your child has a serious side effect such as:
- high fever, ear pain or drainage, tugging at the ear;
- warmth or swelling of the ear;
- crying or fussiness, especially while lying down;
- change in sleeping patterns;
- poor feeding or loss of appetite;
- easy bruising or bleeding; or
- trouble breathing.
Less serious side effects may include:
- low fever;
- cold symptoms such as stuffy nose, sneezing, cough;
- vomiting, diarrhea; or
- pain, redness, or swelling where the shot was given.
Read the entire detailed patient monograph for Synagis (Palivizumab) »
What is Patient Information Overview?
A concise overview of the drug for the patient or caregiver from First DataBank.
Synagis Overview - Patient Information: Side Effects
Remember that the doctor has prescribed this medication because he or she has judged that the benefit to your child is greater than the risk of side effects. Many children using this medication do not have serious side effects.
A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
In the US -
Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
Read the entire patient information overview for Synagis (Palivizumab)»
What is Prescribing information?
The FDA package insert formatted in easy-to-find categories for health professionals and clinicians.
Synagis FDA Prescribing Information: Side Effects
Clinical Studies Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.
The data described below reflect exposure to Synagis (n=1639) compared with placebo (n=1143) in children 3 days to 24.1 months of age at high risk of RSV-related hospitalization in two clinical trials. Trial 1 was conducted during a single RSV season and studied a total of 1502 children less than or equal to 24 months of age with BPD or infants with premature birth (less than or equal to 35 weeks gestation) who were less than or equal to 6 months of age at study entry. Trial 2 was conducted over four consecutive seasons among a total of 1287 children less than or equal to 24 months of age with hemodynamically significant congenital heart disease.
In Trials 1 and 2 combined, fever and rash were each reported more frequently among Synagis than placebo recipients, 27% versus 25%, and 12% versus 10%, respectively. Adverse reactions observed in the 153-patient crossover study comparing the liquid and lyophilized formulations were comparable for the two formulations, and were similar to those observed with Synagis in Trials 1 and 2.
In Trial 1, the incidence of anti-palivizumab antibody following the fourth injection was 1.1% in the placebo group and 0.7% in the Synagis group. In children receiving Synagis for a second season, one of the fifty-six children had transient, low titer reactivity. This reactivity was not associated with adverse events or alteration in serum concentrations. Immunogenicity was not assessed in Trial 2.
A trial of high-risk preterm children less than or equal to 24 months of age was conducted to evaluate the immunogenicity of the lyophilized formulation of Synagis (used in Trials 1 and 2 above) and the liquid formulation of Synagis. Three hundred seventy-nine children contributed to the 4 to 6 months post-final dose analysis. The rate of anti-palivizumab antibodies at this time point was low in both formulation groups (anti-palivizumab antibodies were not detected in any subject in the liquid formulation group and were detected in one subject in the lyophilized group (0.5%), with an overall rate of 0.3% for both treatment groups combined).
These data reflect the percentage of children whose test results were considered positive for antibodies to palivizumab in an enzyme-linked immunosorbent assay (ELISA) and are highly dependent on the sensitivity and specificity of the assay.
The ELISA has substantial limitations in detecting anti-palivizumab antibodies in the presence of palivizumab. Immunogenicity samples tested with the ELISA assay likely contained palivizumab at levels that may interfere with the detection of anti-palivizumab antibodies.
An electrochemical luminescence (ECL) based immunogenicity assay, with a higher tolerance for palivizumab presence compared to the ELISA, was used to evaluate the presence of anti-palivizumab antibodies in subject samples from two additional clinical trials. The rates of anti-palivizumab antibody positive results in these trials were 1.1% and 1.5%.
The following adverse reactions have been identified during post approval use of Synagis. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
General Disorders and Administration Site Conditions: injection site reactions
Limited information from post-marketing reports suggests that, within a single RSV season, adverse events after a sixth or greater dose of Synagis are similar in character and frequency to those after the initial five doses.
Read the entire FDA prescribing information for Synagis (Palivizumab) »
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