Raxibacumab (intravenous)

Raxibacumab is a drug administered intravenously and used in combination with antibiotics to treat and prevent inhalation anthrax.


Raxibacumab is a monoclonal antibody drug that is able to eliminate the toxins in the body that result from an infection with the bacteria that causes inhalation anthrax. When a person inhales the spores that lead to inhalation anthrax, toxins are produced in the body that may quickly lead to tissue destruction and death. The antibiotics that are used to kill the anthrax bacteria are not sufficient to eliminate the toxins from the body, although they do rapidly clear the body of the bacteria.

When raxibacumab was tested in animal studies, the drug was administered approximately 28 hours after the inhalation of anthrax spores. In one study, up to 64 percent of those who were exposed to anthrax survived when raxibacumab was administered. Researchers have found that patients who receive raxibacumab and an antibiotic from the quinolone family together have an 82 percent anthrax survival rate.

Raxibacumab is also used a means to prevent inhalation anthrax in those who may have been exposed to the disease. Anthrax normally occurs among those who work with or near infected cattle or sheep. If anthrax is suspected in an animal population that a person has been working with, raxibacumab may be used to prevent the anthrax bacteria from progressing or establishing in the system.

Raxibacumab is only used for those dealing with inhalation anthrax. There are other types of anthrax such as gastrointestinal anthrax. Raxibacumab has not been tested on other types of anthrax, and it is not recommended as a treatment or for the prevention of any type of anthrax accept for inhalation anthrax.

This drug has side effects associated with the drug itself, and there may be side effects due to the fact that the drug is infused by IV for a period of over two hours. This may cause infusion site side effects and reactions.

This drug is obtained by physicians from the Centers For Disease Control when anthrax is suspected. This drug is only used in a medical setting, and the patient will be isolated so as not to infect others in the area.

Conditions Treated

  • Inhalation anthrax
  • Prevention when inhalation anthrax exposure is suspected

Type of Medication

  • Monoclonal antibody to neutralize B. anthracis toxins in the body.

Side Effects

A number of people who receive this drug develop a rash while the drug is being administered. In order to prevent this type of allergic reaction from occurring, patients will be given a dose of the antihistamine diphenhydramine. This drug is more commonly known as Benadryl. Benadryl is proven to treat skin allergies, especially hives. To prevent allergic reactions in the skin, Benadryl is given in tablet form or through the IV port about one hour before the patient receives the infusion of raxibacumab.

Even when Benadryl is given before the infusion of raxibacumab, approximately 3 percent of patients will still have some form of rash as a side effect of the drug. About 2.5 percent of patients also report a general feeling of itchiness when using the drug.

Another more reported side effect with raxibacumab is pain in the arms and legs. This pain is usually not severe, and it does not usually result in the use of the drug being suspended.

Slightly more than 1 percent of patients report that they have a feeling of deep sleep that comes over them while the drug is being infused. This feeling is usually not persistent.

There are several other side effects that have been reported with the drug that occur more infrequently than those mentioned. Some side effects related to the blood and lymphatic system include anemia, leukemia, and lymphadenopathy. In some patients, the blood levels of creatine phosphokinase and amylase become elevated.

Cardiovascular side effects have been reported with raxibacumab. Patients have reported heart palpations and an increase in blood pressure while on the drug. Flushing is sometimes reported along with a sense of dizziness and vertigo.

A few patients have reported that being on the drug has caused them to experience pain in the back and in other muscles throughout the body. This pain is usually not severe.

As this drug is given through an infusion into the bloodstream, there have been side effects reported in and around the infusion site. Patients have reported pain and redness at the site. Others report itching and swelling around the infusion area.


Before raxibacumab is administered, the patient will receive a dose of Benadryl by mouth or through the infusion site. This dose is usually given about one hour before raxibacumab is infused.

The normal dosage of raxibacumab for an adult patient is 40 mg/kg given over a period of 2.5 hours.

In pediatric patients, the dose of raxibacumab that is administered is based upon the child's weight. Pediatric patients who weigh more than 50 kg are given the same dose as an adult which is 40 mg/kg. Pediatric patients that weigh between 15 kg and 50 kg are given a dose of 60 mg/kg, while pediatric patients who are 15 kg and below are given a dose of 80 mg/kg.

This dosage is given for treating active anthrax and for the prevention of inhalation anthrax.

The drug is supplied as a 1,700mg/50ml solution in a vial for use as a single dose.


Raxibacumab is not known to interact with any other drugs. However, it is important that patients fully inform their healthcare professional regarding any prescription or nonprescription drugs that they are using.

Since Benadryl is administered before the infusion of raxibacumab, it is important not to take any other antihistamines for at least six hours after the Benadryl is administered. Doing so may cause extreme drowsiness. Muscle relaxants and opioid painkillers should also not be used as they may increase drowsiness to an unacceptable level.


Raxibacumab is known to cause allergic reactions in the skin. Benadryl should always be administered approximately one hour before raxibacumab is given to the patient. This will significantly reduce the occurrence of any allergic reactions. However, even with the administration of Benadryl, approximately 3 percent of patients still have a skin reaction to raxibacumab. If side effects do occur, the healthcare provider will deal with these in the healthcare setting. Most side effects with raxibacumab are mild and do not result in the discontinuation of the drug.

This drug is not intended to treat inhalation anthrax on its own. This drug should always be given in conjunction with an antibiotic to make sure that all of the anthrax bacteria and toxins are completely eliminated from the system. The antibiotics that are most used in combination with raxibacumab are those in the quinolone family which includes the drugs Cipro and Levaquin.

This drug is listed as Pregnancy Category B. This drug is not considered to be harmful to women who are pregnant. The drug has not been tested on nursing mothers, so mothers who are breastfeeding may want to suspend breastfeeding while the drug is in their system.

No testing has been done with pediatric patients who are using this drug. There are dosage recommendations supplied for pediatric patients, and at this time the drug is considered safe for pediatric use.

This drug is only to be used for the treatment of inhalation anthrax. It is not considered to be effective against other forms of the disease, nor is it considered adequate to treat any form of brain-based infection as the drug does not pass the blood/brain barrier.


This drug needs to be refrigerated between the temperatures of 36 to 46 degrees Fahrenheit. The drug should not be in the presence of bright light before it is intended for use.


Raxibacumab is a monoclonal antibody drug that is used in a clinical setting in order to eliminate the toxins in the body produced by the anthrax bacteria. The drug is also used to help prevent inhalation anthrax when someone may have potentially been exposed to the disease. Raxibacumab is not designed to treat any other form of anthrax except inhalation anthrax.

This drug is not used by itself to treat anthrax. Raxibacumab is always used in combination with antibiotic drugs to ensure that all of the anthrax bacteria and toxins are eliminated from a patient's system.

There are several different types of side effects associated with the use of this drug. The most common side effect is an allergic reaction that manifests as a rash. In order to mitigate this potential side effect, all patients are given a dose of Benadryl one hour prior to receiving an infusion of raxibacumab. Even when Benadryl is administered, roughly 3 percent of patients still report a rash and itching.

Most of the side effects reported with raxibacumab are mild. This drug is used in a hospital or doctor's office, so side effects are dealt with as they occur during infusion.

There are no drug interactions known with this drug.

Last Reviewed:
February 02, 2018
Last Updated:
April 09, 2018