Palivizumab - Indications, Dosage, and Side Effects

What Is Palivizumab?

Palivizumab is a medicine that helps protect kids from the respiratory syncytial virus (RSV) (a virus that infects the lungs and can seriously impair breathing). Premature infants and kids with specific heart or lung disorders are the main recipients. Children who are 24 months or younger at the beginning of the RSV season respond best to the medication.

Palivizumab works by preventing the virus from proliferating within the body. Although it offers short-term protection, it does not treat RSV. It is administered as a muscle injection once a month during the RSV season, and each dose shields the child for roughly one month. Children who have previously experienced severe allergic reactions should not be administered this medication. Mild fever is a common side effect of Palivizumab.

Drug Group

Palivizumab is a monoclonal antibody drug that prevents virus replication and belongs to the class of immunoglobulins. Immunoglobulins enhance the body's immune system, reducing infection risk in weakened individuals derived from healthy human blood with high levels of protective antibodies.

How Does Palivizumab Work?

A monoclonal antibody called Palivizumab binds to the RSV fusion protein A's surface. This protein prevents RSV infection by preventing the virus from entering bodily cells, especially those in the lungs. The fusion (F) glycoprotein on the surface of RSV, a membrane protein that fuses the virus with its target cell, is bound by Palivizumab and rendered inactive. The immune system uses this mechanism to help stop or slow the virus's spread throughout the body. Among RSV subgroups, Palivizumab, which is administered by injection, is highly conserved.

For Patients

What Are the Clinical Uses of Palivizumab?

• Palivizumab is a drug used in high-risk pediatric patients to prevent serious lower respiratory tract infections caused by RSV (respiratory syncytial virus).

• In these high-risk patients, it may minimize the severity of RSV infection and hospitalizations.

• Premature newborns, infants with a history of bronchopulmonary dysplasia (a type of chronic lung illness affecting newborns, many of whom are premature and require oxygen therapy), and infants with hemodynamically significant congenital heart disease are all suitable for the medication.

• However, it is not intended for adults or immunocompromised children and does not treat active RSV infection.

Contraindications:

Palivizumab is contraindicated in those with prior severe allergic reactions to the drug or its components.

Dosage Forms and Available Strengths:

• Palivizumab is a single-dose liquid solution comprising 50 mg (milligrams) per 0.5 mL (milliliter) and 100 mg per mL, and 15 mg per kg (milligrams per kilogram) of body weight is indicated for children with RSV (respiratory syncytial virus) infections, administered monthly intramuscularly.

• The first dose should be provided before the start of the respiratory syncytial virus season, and the following doses should be administered monthly throughout.

• Palivizumab should be given to children who have undergone cardiopulmonary bypass (a surgical procedure where a machine temporarily replaces the heart and lungs, ensuring the body’s blood and oxygen circulation) as soon as feasible following the procedure and then monthly after that.

How Does Palivizumab Work?

A monoclonal antibody called Palivizumab binds to the RSV fusion protein A's surface. This protein prevents RSV infection by preventing the virus from entering bodily cells, especially those in the lungs. The fusion (F) glycoprotein on the surface of RSV, a membrane protein that fuses the virus with its target cell, is bound by Palivizumab and rendered inactive. The immune system uses this mechanism to help stop or slow the virus's spread throughout the body. Among RSV subgroups, Palivizumab, which is administered by injection, is highly conserved.

How Is Palivizumab Administered?

• Palivizumab is an antiviral medicine injected intramuscularly (IM), preferably in the anterolateral part of the thigh, by a doctor or nurse.

• During expected periods of RSV risk in the community, providing 15 mg/kg of body weight is recommended once a month. The first dose should be delivered prior to the onset of the RSV season, with further doses administered monthly throughout the season.

• In the northern hemisphere, the RSV season typically begins in November and lasts until April, but it may begin earlier or continue longer in certain regions. Children who contract RSV should continue to receive monthly dosages throughout the season.

• It is critical to discuss with the doctor the number of injections the kid will require and when the shots will be administered.

• If the child has undergone surgery for certain heart conditions, an additional dose may be required shortly after. To avoid serious sickness from new infections, it is critical to address the symptoms of RSV disease with a healthcare professional.

What Are the Side Effects of Palivizumab?

More common side effects are:

• Fever.

• Rash.

• Swelling, pain, or redness where the injection was made.

• Mild respiratory symptoms, including a runny nose and cough.

• Diarrhea (loose stool).

• Headache.

If any of the following side effects develop while taking Palivizumab, contact the doctor right away:

• The color of the fingernails, lips, skin, palms, or nail beds is bluish.

• Blurred vision.

• Confusion.

• Cough.

• Breathing difficulties.

• Swallowing difficulties.

• Dizziness, faintness, or lightheadedness upon abruptly rising from a sleeping or seated posture.

• Rapid heartbeat.

• Welts or hives.

• Breathing that is uneven, rapid, slow, or shallow.

• Itching.

• Hive-like swelling of the face, eyes, lips, tongue, throat, hands, legs, feet, or genital organs.

• Strength or energy loss.

• Discomfort or weakening of the muscles.

• Sweating.

• Chest constriction.

• Unresponsiveness.

• Unexpected exhaustion or weakness.

• Wheezing.

What Are the Things to Inform the Doctor Before Taking Palivizumab?

Here are some essential things to inform the doctor before starting Palivizumab treatment:

• Inform the doctor if the child is allergic to Palivizumab, any other drugs, or any ingredients in the Palivizumab injection.

• Inform the doctor about any additional prescription and over-the-counter (OTC) drugs, vitamins, nutritional supplements, and herbal products the child intends to take. Make sure to mention if the child is on anticoagulants (also known as blood thinners). The doctor may need to adjust the child's medication dosages or closely watch for negative effects.

• Inform the doctor if the child has a low platelet count or has ever had a bleeding disorder.

• If the child is undergoing dental surgery, inform the doctor or dentist that the child receives a Palivizumab injection.

Dietary Considerations: None

Missed Dose:

Contact the doctor immediately if the child fails to appear for a Palivizumab injection appointment.

Overdose:

In case of an overdose, seek immediate medical attention. Contact emergency services right away if the patient is unconscious, has a seizure (uncontrollable electrical activity), trouble breathing.

Storage:

Palivizumab should be kept in its original container between 2 and 8 degrees Celsius (36 and 46 degrees Fahrenheit), not frozen, and not used after its expiration date.

For Doctors

Chemical Taxonomy for Palivizumab

• Type: Monoclonal antibody.

• Class: Immunoglobulin G1 (IgG1).

• Target: Fusion protein of respiratory syncytial virus (RSV).

• Origin: Humanized monoclonal antibody.

• Mechanism: Binds to the RSV fusion protein to prevent viral entry into host cells.

• Use: Prevents viral entry into host cells by binding to RSV fusion protein.

Pharmacodynamics

Palivizumab inhibits the respiratory syncytial virus (RSV). It helps stop the virus from growing and spreading throughout the body by neutralizing it and preventing it from fusing with cells. Children are administered it to help prevent severe lower respiratory tract infections caused by RSV.

Mechanism of Action

Palivizumab binds to the RSV fusion glycoprotein. This stops it from attaching to and being taken up by host cell receptors.

Pharmacokinetics

• Palivizumab has a pharmacokinetic profile similar to that of a human IgG1 antibody in terms of volume of distribution and half-life.

• Palivizumab is most likely eliminated through opsonization by the reticuloendothelial system.

• Palivizumab’s half-life is stated to be 18 days on average.

• However, according to other sources, the half-life can range from 17 to 26.8 days.

• It should be noted that these values are based on adult volunteer studies, and only trough serum concentrations were recorded in the critical pediatric clinical efficacy study.

• Individual patient features, like with any medicine, might alter pharmacokinetics.

• For information suited to individual patient needs, always consult a healthcare provider.

Warnings and Precautions

The warnings and precautions associated are as follows:

• Hypersensitivity Reactions: There have been reports of severe allergic reactions following the initial or subsequent doses of Palivizumab, including anaphylaxis and anaphylactic shock. These reactions have occasionally been lethal. Following initial use or re-exposure, additional severe allergic reactions have also been observed.

Hives, itching, facial or lip swelling, breathing difficulties, breathing failure, bluish skin, low muscle tone, low blood pressure, or loss of responsiveness are some symptoms. The development of antibodies against Palivizumab has not been linked to these reactions.

Palivizumab must be stopped right away if a severe allergic reaction happens. Emergency treatments like Epinephrine and supportive care should be administered immediately in cases of severe allergy or anaphylaxis.

• Coagulation Disorders: Palivizumab is only for intramuscular use. Like any intramuscular injection, Palivizumab should be administered carefully to children with thrombocytopenia or another clotting condition.

• RSV Diagnostic Test Interference: Palivizumab suppresses virus reproduction in cell culture. It may interfere with immunological RSV diagnostic tests, such as antigen detection and viral culture assays. Reverse transcriptase polymerase chain reaction assays may not be affected and result in false-negative results. Therefore, diagnostic test results should be combined with clinical findings for medical decision-making.

• Treatment of RSV Disease: Palivizumab's safety and efficacy for treating RSV disease have not been demonstrated.

• Proper Administration: A preservative is not present in the single-dose vial of Palivizumab. Palivizumab should be administered once the dose is removed from the vial. It is not necessary to re-enter the vial. Any unused portion should be discarded.

Drug Interactions:

With no official drug-drug interaction investigations, a clinical study found no significant increase in adverse events among children getting regular childhood immunizations, influenza vaccines, bronchodilators, or corticosteroids (such as Prednisone, Hydrocortisone, Betamethasone).

Clinical Studies:

For children who are at high risk of hospitalization, Palivizumab is used to help prevent severe RSV infection. Two extensive clinical trials examined its efficacy and safety. In one study, 1502 infants under 24 months old with bronchopulmonary dysplasia or premature birth were included. There were 1287 children with severe congenital heart disease in the second study.

For five months, children in both trials received a muscle injection of either a placebo or Palivizumab at a dose of 15 milligrams per kilogram of body weight. According to the findings, children who received Palivizumab had a significant decrease in hospitalizations due to RSV.

Palivizumab did not, however, make the illness less severe in children who were hospitalized with RSV than in those who received a placebo. Overall, the findings from the study discussed above, the drug seems to be effective.

Use in Specific Populations

• Pregnancy: Palivizumab is not recommended for adult use. When delivered to a pregnant woman, it is unknown whether Palivizumab can cause fetal damage or alter reproductive potential.

• Pediatric Use: Palivizumab's safety and efficacy for children over 24 months at the beginning of dosing are yet to be established.