Patient education: Intravenous immune globulin (IVIG) (Beyond the Basics)

WHAT IS IVIG? — Intravenous immune globulin ("IVIG") is a product made up of human antibodies that can be given intravenously (through a vein).

Antibodies are proteins your body makes to help you fight certain infections. Each antibody made by your body is slightly different because it fits like a lock and key to every foreign substance (such as a piece of a virus or bacterium) that gets into your body. Over the course of your life your body makes thousands of different antibodies as you are exposed to different infectious organisms that your body considers to be "foreign."

Your body makes many different antibodies against different parts of the same foreign organisms, so IVIG can be very effective at preventing or treating infections in persons who do not have antibodies or who have low levels of antibodies.

IVIG is prepared from the blood donated by thousands of people, to make a super-concentrated and very diverse collection of antibodies against many possible infectious organisms your body might encounter.

WHY DO I NEED IVIG? — IVIG is used primarily in two situations.

One reason you might need IVIG is if your body does not make enough antibodies. This is called "humoral immunodeficiency." The IVIG simply provides extra antibodies that your body cannot make on its own. The antibodies usually last for several weeks to months and help your body fight off a large variety of infections before they become serious (or before you even know you have them). If you are getting IVIG for this reason, you will need to get it on a regular schedule.

A second reason you might need IVIG is if your immune system attacks a certain type of cell or protein in your own body (autoimmune disease). Conditions in which this happens include:

●Destruction of your own blood platelets (known as immune thrombocytopenia [ITP])

●Destruction of your own red blood cells (known as autoimmune hemolytic anemia [AIHA])

●Attack on your nervous system, such as nerves that control your breathing (in Guillain-Barré syndrome) or nerves that control sensation (for example, in chronic inflammatory demyelinating polyneuropathy [CIDP])

Experts believe IVIG prevents your immune system from destroying your own cells in these disorders. The extra antibodies are thought to overwhelm the immune system in some way and prevent the attack on your own cells.

HOW IS IVIG GIVEN? — IVIG is given into a vein ("intravenously"), in an infusion that usually takes one to four hours. The amount of IVIG you need for each dose depends on your weight as well as the reason you are getting the IVIG:

●If the purpose is to replace the antibodies your body should be producing, IVIG is given as smaller doses administered on a regular schedule. Your doctor will determine how often you need IVIG and how long you will need to continue to get IVIG (this may need to be reviewed periodically depending on your diagnosis).

An alternative to IVIG for providing antibodies is to receive the antibodies under the skin, referred to as subcutaneous immune globulin (SCIG). Your doctor can let you know if this is an option for you.

●If the purpose is to block your immune system from attacking your own body, IVIG is given as a few large doses (occasionally a single dose). Your doctor can usually tell whether the IVIG is working after one or a few doses.

There are a number of different brands of IVIG. In general, if you are going to be receiving IVIG on a regular basis, it may be best to use the same brand every time to reduce the risk of side effects.

IVIG usually is given in a doctor's office or hospital. In some cases, it may be given in the home, if proper arrangements are made, but this is not common. It is important that you are comfortable with where you will be receiving your IVIG and that you let the doctor or nurse know if you have any questions or concerns.

IVIG SIDE EFFECTS — Many people do not have side effects from IVIG, but there are some possible side effects, especially if you are not receiving the IVIG on a regular basis and/or if you are receiving larger doses of IVIG. Over the course of treatment, approximately one-fourth of persons may experience a side effect. These are usually mild or bothersome but not dangerous. Very rarely, more serious side effects like allergic reactions or low blood counts (anemia) can occur.

One of the most common side effects is headache. Other side effects include chills, fever, flushing, flu-like muscle pains or joint pains, feeling tired, having nausea, vomiting, and rash. For the most part, these reactions typically happen with the first dose of IVIG or if you change to a different brand of IVIG. You will be watched for these and other reactions.

Side effects that can happen a day or more after you receive IVIG include rashes and low blood counts.

Your doctor may do several things to reduce the chance of having these side effects, including:

●Performing certain blood tests before the IVIG is started.

●Keeping you well hydrated, in some cases giving extra fluids (by mouth or intravenously).

●Giving IVIG more slowly.

●Dividing a large dose into several smaller doses that are given over several days.

●Giving you medications that reduce pain and fever prior to your IVIG – These may include acetaminophen (sample brand name: Tylenol); a nonsteroidal antiinflammatory drug or "NSAID" such as ibuprofen (sample brand names: Advil, Motrin) or naproxen (sample brand name: Aleve); or steroids. However, many people do not require these medications before the IVIG is given.

●Doing blood tests after IVIG is given.

Some people worry about contracting a disease through IVIG, since it is made from blood donated by other people. The risk of getting a viral infection from IVIG is considered exceedingly low. No one has ever gotten HIV (the virus that causes AIDS) from IVIG, and the methods used to purify IVIG will destroy bacteria, hepatitis viruses, and other infectious diseases.

However, no one can predict every new infection that may develop. This is one of the reasons IVIG is only given when it is really needed, and records of the specific IVIG product number are kept.

ARE THERE ANY ALTERNATIVES TO IVIG? — If you are receiving IVIG to provide extra antibodies, immune globulin that can be given subcutaneously (as an injection under the skin) can also be used. Subcutaneous immune globulin (SCIG) has fewer side effects and may be a good option for some people.

If you are receiving IVIG to block your immune system from attacking your own cells, there are several alternative medicines that can control your immune system:

●Commonly used medicines to block the immune system include glucocorticoids (steroids) like prednisone and dexamethasone or certain medicines that target antibody-producing cells, like rituximab (brand name: Rituxan). However, these medicines often take several days or weeks to work, so IVIG may be a good option if you need a treatment that works rapidly.

●Another form of antibodies called RhD immune globulin (sample brand name: RhoGam/WinRho) can also be used. RhD immune globulin is also prepared from blood donated by thousands of people; it is sometimes given during pregnancy to prevent problems related to the baby having a different blood type from the mother. RhD immune globulin can also be used to block the immune system.

IS THERE ANYTHING ELSE I NEED TO KNOW? — Vaccines may not work as well in the weeks to months after the IVIG is given because the IVIG may block the immune system from responding appropriately to the vaccine. However, it is important to get certain vaccines, and you are better protected if you get the vaccines than if you do not. Discuss the best timing with your doctor.

Keep records of the product number and date you received your IVIG infusions. This is important for keeping track of which products worked best for you and for testing if you think you had a side effect related to the IVIG.

If a specific brand of IVIG is working well for you, it is safer not to substitute a different brand.

WHERE TO GET MORE INFORMATION — Your health care team is the best source of information for questions and concerns related to your medical problem.

This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for health care professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient education: Immune thrombocytopenia (ITP) (The Basics)
Patient education: Guillain-Barré syndrome (The Basics)
Patient education: Autoimmune hemolytic anemia (The Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Overview of intravenous immune globulin (IVIG) therapy
Immune globulin therapy in inborn errors of immunity
Intravenous immune globulin: Adverse effects
Subcutaneous and intramuscular immune globulin therapy

The following organizations also provide reliable health information.

●American Academy of Allergy, Asthma, and Immunology (https://www.aaaai.org/)