Antiviral Agents: Immune Globulin

Immune Globulin

Immune globulin ( γ-globulin, immunoglobulin [Ig] G) is a fraction obtained from the plasma of normal indi-viduals and is rich in antibodies found in whole blood.

It consists primarily of IgG and contains trace amounts of IgA and IgM. -Globulin provides the patient with passive immunity and does not require time for the de-velopment of an antibody response. It is believed to in-hibit viral penetration of host cells, opsonize viral parti-cles, activate complement, and stimulate cell-mediated immunity.

Absorption, Metabolism, and Excretion

γ-Globulin is administered parenterally. Intramuscular or intravenous injections are given during the early in-fectious stage to alleviate the progression of certain vi-ral disorders. Protection lasts for 2 to 3 weeks after a single injection, although for prolonged infections, in-jections can be repeated every 2 to 3 weeks.

Clinical Uses

Human immune globulin preparations specifically for the treatment and/or prevention of CMV (CytoGam), HBV (BayHep B), rabies (BayRab), RSV (RespiGam), and VZV (VZIG) are obtained from individuals with high titers of antibodies against these viruses. A pooled het-erogeneous human immune globulin solution (BayGam, Gamimmune, others) can be used to lessen the likelihood of measles, varicella, or rubella infection in individuals ex-posed to these viruses. Immune globulin also can be used as an adjunctive form of therapy with other therapeutic approaches.

Adverse Effects, Contraindications, and Drug Interactions

Hypersensitivity reactions (e.g., anaphylaxis, angio-edema) associated with -globulin are rare but occur most commonly in individuals with agammaglobuline-mia, severe hypogammaglobulinemia, or IgA deficiency. The likelihood of anaphylactoid reaction increases fol-lowing repeated dosing and for certain preparations, in-travenous administration. Immune globulins can also cause urticaria, angioedema, fever, and injection site re-actions. Preparations that are administered intra-venously (e.g., RSV immune globulin) can produce in-fusion-related side effects such as flushing, dizziness, blood pressure changes, palpitations, abdominal cramps, and dyspnea; slowing the infusion rate may reduce the severity of these effects. High doses of immune globu-lins have been associated with rare cases of aseptic meningitis syndrome. A possibility of infection by blood-borne pathogens exists with immune globulin and other human blood products. Although prepara-tions are screened for contamination and viral inactiva-tion processes are used, the risk of transmission of new or undetected pathogens cannot be eliminated.

Treatment with immune globulin can interfere with the response to live virus vaccines (e.g., measles, mumps, rubella). Vaccinations should be deferred until several months after the administration of -globulin because the antibodies contained in this preparation may interfere with the development of the host immune response. Individuals who were vaccinated shortly be-fore receiving immune globulin may require revaccina-tion at a later time.