Synagis

Respiratory Syncytial Virus (RSV) Antivirals

Visually inspect parenteral products for particulate matter and discoloration prior to administration whenever solution and container permit.

Preparation
Do not dilute the solution prior to intramuscular administration.
Do not shake or vigorously agitate the vial.
Administer the dose immediately after withdrawing from the vial into a sterile syringe.
The solution for injection is preservative-free and is supplied as single-use vials. Discard any unused portion.
 
IM Injection
Divide doses greater than 1 mL and inject into different sites.
Inject into the anterolateral aspect of the thigh. In order to avoid injury to the sciatic nerve, injection into the gluteus maximus is not recommended.

anaphylactic shock / Rapid / 0-0.1
anaphylactoid reactions / Rapid / Incidence not known
angioedema / Rapid / Incidence not known
cyanosis / Early / Incidence not known
arrhythmia exacerbation / Early / Incidence not known

elevated hepatic enzymes / Delayed / 2.3-3.6
antibody formation / Delayed / 0.5-1.5
erythema / Early / 1.4-1.4
dyspnea / Early / Incidence not known
wheezing / Rapid / Incidence not known
thrombocytopenia / Delayed / Incidence not known

infection / Delayed / 50.6-50.6
fever / Early / 27.1-27.1
rhinitis / Early / 26.8-26.8
rash / Early / 0.9-12.0
injection site reaction / Rapid / 2.3-2.3
pruritus / Rapid / Incidence not known
urticaria / Rapid / Incidence not known
cough / Delayed / Incidence not known
diarrhea / Early / Incidence not known
vomiting / Early / Incidence not known

Synagis

Rx

Recombinant monoclonal antibody that provides passive immunity against respiratory syncytial virus (RSV)
Used for RSV prevention in high risk infants and children; not approved for RSV treatment
Administered monthly during RSV season

15 mg/kg/dose IM once monthly. Administer the first dose prior to commencement of RSV season and continue monthly throughout the RSV season. Generally, limit to 5 monthly doses per RSV season; however, AAP supports providing more than 5 consecutive doses of palivizumab to eligible children in regions with widespread and intense RSV circulation. If the patient undergoes cardiopulmonary bypass or extracorporeal membrane oxygenation, administer 15 mg/kg IM of palivizumab as soon as possible after the procedure, even if it has been less than 1 month since the previous dose.

15 mg/kg/dose IM once monthly. Administer the first dose prior to commencement of RSV season and continue monthly throughout the RSV season. Generally, limit to 5 monthly doses per RSV season; however, AAP supports providing more than 5 consecutive doses of palivizumab to eligible children in regions with widespread and intense RSV circulation. If the patient undergoes cardiopulmonary bypass or extracorporeal membrane oxygenation, administer 15 mg/kg IM of palivizumab as soon as possible after the procedure, even if it has been less than 1 month since the previous dose.

Specific guidelines for dosage adjustments for hepatic impairment are not available; it appears that no dosage adjustments are needed.

Specific guidelines for dosage adjustments in renal impairment are not available; it appears that no dosage adjustments are needed.

There are no drug interactions associated with Palivizumab products.

Palivizumab (Murine)/Synagis Intramuscular Inj Sol: 0.5mL, 1mL, 50mg, 100mg

Safety and efficacy have not been established. 

Safety and efficacy have not been established. 

Safety and efficacy have not been established. 

3 to 12 years: Safety and efficacy have not been established.
1 to 2 years: 15 mg/kg/dose IM.

15 mg/kg/dose IM.

15 mg/kg/dose IM.

Palivizumab exhibits neutralizing and fusion-inhibitory activity against RSV. Palivizumab is directed at an epitope in the A antigenic site of the 'F' protein on the surface of RSV. Palivizumab binds to this epitope, which is highly conserved among different RSV isolates. Thus, palivizumab interferes with the ability of RSV to replicate and infect cells. In laboratory studies, palivizumab neutralized 57 strains of RSV tested. Clinically, tracheal isolates from intubated children with RSV infection have shown significantly reduced quantities of RSV in the lower respiratory tract after palivizumab administration when compared to controls. Because palivizumab is not derived from human immune globulin, it is free of potential contamination by infectious agents and does not contain antibodies directed at other viruses or illnesses.
 
Further data are needed, but the use of palivizumab prophylaxis in the community does not appear to cause palivizumab-resistant RSV strains. Of 371 RSV strains obtained from children hospitalized for RSV in 8 different communities in the U.S., all were found to bind to palivizumab. Also, 25 of the 371 strains were from children that received palivizumab during the current season, although the average exposure duration was only 2 months (range of 1—5 monthly doses). The strains were obtained during the 4 RSV seasons of 1998—2002, which is during the time period that palivizumab was in use.

Palivizumab is administered via intramuscular injection. In clinical models of RSV infection, palivizumab serum concentrations of 40 mcg/mL or more are associated with 99% reductions in pulmonary RSV replication. The half-life of palivizumab is approximately 20 days in pediatric patients 24 months and younger without congential heart disease (CHD).
 
Affected cytochrome P450 isoenzymes: none

In a population pharmacokinetic analysis in 1,800 patients (1,684 pediatric and 116 adult patients), the elimination half-life was 24.5 days in pediatric patients. In pediatric patients 24 months and younger without congenital heart disease (CHD), the bioavailability was 70% and clearance was 11 mL/day. The interpatient variability in drug clearance was 48.7%; covariate analysis did not identify any factors that could account for the interpatient variability. Monthly intramuscular doses of 15 mg/kg achieved mean trough serum drug concentrations of 37 +/- 21 mcg/mL after the first injection, 57 +/- 41 mcg/mL after the second injection, 68 +/- 51 mcg/mL after the third injection, and 72 +/- 50 mcg/mL after the fourth injection. In children given palivizumab for a second season, the mean serum concentrations after the first and fourth injections were 61 +/- 17 mcg/mL and 86 +/- 31 mcg/mL, respectively.

Palivizumab has been classified as FDA pregnancy risk category C. Studies in animal or human reproduction have not been conducted. It is unknown if palivizumab can cause fetal harm or affect reproductive capacity.

Palivizumab is not approved for use in women of childbearing age and data regarding its' administration during breast-feeding is unavailable. The manufacturer does not state whether the drug is excreted in human milk.