anthrax immune globulin

Action and Spectrum

Actions and spectrum: 

anthrax immune globulin (AIG) is a polyclonal antibody product used for the treatment of anthrax infection caused by Bacillus anthracis. AIG is derived from the plasma of immunized human donors and contains antibodies against the protective antigen (PA) component of the anthrax toxin. 

When B. anthracis bacteria are introduced into the body, they produce three toxins: lethal toxin, edema toxin, and PA. PA is necessary for the toxins to enter cells, and it is the primary target of AIG.

AIG binds to PA and neutralizes its activity, preventing it from facilitating the entry of lethal and edema toxins into cells. By doing so, AIG can prevent the development of anthrax infection or halt its progression. 

Drug Interaction

Adverse Reaction

Frequency defined 

1-10% 

Back pain (3.7%) 

Swelling at Infusion site (7.4%) 

Pain at Infusion site (9.3%) 

Nausea (9.3%)  

>10% 

Headache (20.4%) 

Black Box Warning

Black Box Warning: 

There is no black box warning associated with the use of anthrax immune globulin. 

Contraindication / Caution

Contraindication/Caution: 

Contraindication: 

anthrax immune globulin (AIG) is contraindicated in patients with hypersensitivity to immunoglobulin products. It should also not be administered to patients who have had a severe or immediate reaction to a previous dose of AIG.  

Caution: 

• Hypersensitivity reactions: anthrax immune globulin is derived from human plasma and may cause allergic reactions in individuals who are sensitive to blood products or any of the components of the product. 
• Thrombosis: The use of anthrax immune globulin may have an increased risk of thrombosis in patients with a history of thrombosis, coronary artery disease, or other cardiovascular risk factors. 
• Interference with serological testing: The administration of anthrax immune globulin may interfere with certain serological tests, making it difficult to interpret the results. 
• Infection risk: Administration of anthrax immune globulin does not provide protection against future anthrax infection and other protective measures should be taken to avoid exposure to anthrax spores. 
• Administration precautions: anthrax immune globulin should be administered under medical supervision with appropriate equipment and medications available to treat hypersensitivity reactions if they occur. 
• Hepatitis and HIV transmission: As with all human blood-derived products, there is a risk of transmitting infectious agents such as hepatitis B, hepatitis C, or HIV, although this risk is considered low due to the manufacturing process and rigorous screening of plasma donors.

Comorbidities: 

There is no specific information on comorbidities of anthrax immune globulin. However, caution should be exercised when administering anthrax immune globulin to individuals with a history of allergy or hypersensitivity reactions to human immunoglobulin products. 

Pregnancy / Lactation

Pregnancy consideration: N/A 

Lactation: N/A  

Pregnancy category: 

• Category A: Satisfactory and well-controlled studies show no risk to the fetus in the first or later trimester. 
• Category B: There is no evidence of risk to the fetus found in animal reproduction studies and there are not enough studies on pregnant women. 
• Category C: Adverse effects on the fetus found with evidence in animal reproduction studies and no adequate evidence for an effect in humans, care must be taken for potential risks in pregnant women. 
• Category D: There is adequate data available with sufficient evidence of human fetal risk from various platforms, but despite potential risks may be used only in emergency cases for potential benefits. 
• Category X: Drugs listed in this category outweigh risks over benefits These category drugs should be prohibited for pregnant women. 
• Category N: There is no data available for the drug under this category. 

Pharmacology

Pharmacology: 

anthrax immune globulin (AIG) specifically targets the protective antigen (PA) component of anthrax toxin and neutralizes the effects of anthrax toxin. When administered intravenously, AIG binds to circulating PA, forming a complex that prevents it from binding to and entering cells. This prevents the subsequent steps in the pathogenesis of anthrax, including the formation of lethal toxin and edema toxin, and prevents the systemic effects of anthrax infection. 

AIG has no direct antibacterial activity and is not effective against Bacillus anthracis organisms that have already entered cells and begun to produce toxin. As such, it is not a substitute for antimicrobial therapy in the treatment of anthrax infection. Rather, it is intended to be used as an adjunct to antimicrobial therapy in the management of severe, life-threatening cases of anthrax, where the systemic effects of anthrax toxin are a major contributing factor to morbidity and mortality.  

Pharmacodynamics: 

The pharmacodynamics of AIG is based on its ability to neutralize the PA component of anthrax toxin. PA binds to host cell receptors and then forms a complex with the other two components of anthrax toxin, edema factor (EF) and lethal factor (LF), allowing them to enter host cells. Once inside, EF and LF disrupt cellular processes, leading to edema and tissue damage. 

AIG neutralizes PA by binding to it and preventing it from binding to host cell receptors, thereby preventing the formation of the anthrax toxin complex and subsequent cellular damage. AIG does not bind to EF or LF directly, but by neutralizing PA, it indirectly inhibits their activity. 

The onset of action of AIG is immediate upon administration, as it begins to neutralize circulating PA. The duration of action depends on the dose and frequency of administration, as well as the rate of clearance from the body.  

Pharmacokinetics: 

Absorption 

anthrax immune globulin is administered intravenously, which means it bypasses the gastrointestinal tract and is directly delivered to the bloodstream. 

Distribution 

The distribution of anthrax immune globulin may be influenced by factors such as the dose administered, patient factors, and the presence of any co-administered medications. It is expected to distribute into the extracellular fluid and interstitial spaces of the body. It may also cross the placenta and distribute into breast milk. 

Metabolism 

anthrax immune globulin is a protein, and as such, it is not metabolized in the traditional sense like small molecule drugs. Instead, it gets broken down by proteolytic enzymes into amino acids, which can be recycled by the body for various purposes. 

Elimination and excretion 

The excretion and elimination of anthrax immune globulin have not been specifically studied. However, as with other immunoglobulin G (IgG) antibodies, it is expected to be catabolized into amino acids and small peptides, which are then eliminated via normal metabolic pathways. The half-life of anthrax immune globulin is approximately 21 days, which suggests that it is eliminated from the body slowly. 

Adminstartion

Administration: 

anthrax immune globulin is administered intravenously (IV) by a healthcare professional in a hospital or clinical setting. The duration and dosage of treatment may vary based on the severity of infection and the patient’s response to the treatment. It is usually given in combination with antibiotics and other supportive care.

Patient Information Leaflet

Patient information leaflet 

Generic Name: anthrax immune globulin 

Pronounced: (AN-thracks ih-MYOON GLAH-byoo-lin)  

Why do we use anthrax immune globulin? 

anthrax immune globulin (AIG) is a medication that is used on both adults and children to treat inhalational anthrax caused by Bacillus anthracis along with the appropriate antibacterial drugs and to prevent inhalational anthrax when other treatments are not available or are not appropriate. AIG works by neutralizing the toxins produced by the bacteria, which can help reduce the severity of the infection and improve the patient’s chances of survival.