Obiltoxaximab (Intravenous)


A key component of the anthrax toxin is the protective antigen, often referred to as the 'PA'. This is what enables anthrax to enter cells and damage them. If this damage continues, it can cause significant harm to the host organism and can be fatal. Obiltoxaximab works by binding to the protective antigen of the anthrax bacteria, preventing anthrax from entering cells and destroying them.

Obiltoxaximab can cause allergic reactions, including anaphylaxis in some people. It is only administered by trained medical professionals with access to equipment that can help them deal with any allergic reactions that may occur. This medication is usually given alongside other medications that reduce the risk of allergic reactions.

Obiltoxaximab is also usually administered alongside some antibiotic drugs, such as levofloxacin, ciprofloxacin and doxycycline. Studies suggest that the survival rates from anthrax exposure can be significantly improved when these drugs are also taken in conjunction with obiltoxaximab.

Intravenous obiltoxaximab is commonly sold under the brand name Anthim.

Conditions Treated

  • Inhalational anthrax

Type Of Medicine

  • Monoclonal antibody

Side Effects

As well as the desired effect of the medication, obiltoxaximab injections may cause unpleasant side effects in some people.

Obiltoxaximab is known to cause allergic reactions in some individuals, including anaphylaxis, which, in extreme cases, can be fatal. When this medication is given, it is because a doctor has determined that this risk caused by the medication is lower than the risk caused by the exposure to anthrax.

When you are given obiltoxaximab, you will be monitored closely by medical professionals who have been trained to recognise and treat allergic reactions, such as anaphylaxis. However, you should seek assistance from the doctor or nurse if you experience any of the following symptoms:

  • Any difficulty in breathing, including quicker breathing, irregular breathing, coughing and wheezing
  • Difficulty swallowing
  • Discomfort in the chest area
  • Dizziness or disorientation
  • Fainting or loss of consciousness
  • Fast heartbeat
  • Fatigue or weakness
  • Itching or swelling particularly when occurring in the face, tongue or throat
  • Rashes, hives or redness in any part of the skin

Obiltoxaximab can also cause other side effects that are less serious, but still unpleasant to experience. These include:

Common Side Effects

Less Common Side Effects

  • Aches or pain in the muscles, particularly in the arms and legs
  • Changes in body temperature, including chills or fever
  • Congestion in the ears
  • Loss of voice
  • Pain, bruising or irritation in the area of the body you were injected
  • Runny or congested nose
  • Sore throat
  • Sneezing

Rare Side Effects

  • Dry mouth
  • Muscle cramps or stiffness
  • Pain in the bones
  • Painful or swollen joints

Everybody responds to medication in unique ways, so it is possible that you will experience side effects that are not listed above when you are given an obiltoxaximab injection. In many cases, side effects are uncomfortable, but will disappear on their own over time, and will not cause any long-term harm. However, in other cases, side effects may be dangerous, and may require additional medical care. Be aware of your body after you are given this medication, and if you identify any unusual or concerning side effects, seek the assistance of the doctor or nurse on duty.

To help prevent or minimize the impact of side effects, you will usually be given additional medications that will help to reduce your risk of an allergic reaction, such as diphenhydramine. In one study of obiltoxaximab's side effects, 42% of patients who took diphenhydramine beforehand experienced an adverse side effect of some kind, compared to 58% of the people who were not given diphenhydramine. However, diphenhydramine itself can cause drowsiness in some people.


Obiltoxaximab will be administered by a doctor, nurse or another medical professional. They will determine the appropriate dose for you and inject the medication directly into a vein with a needle. You will not be given this medication to take home with you to administer yourself.

The doses of obiltoxaximab that would typically be given, following an initial dose of diphenhydramine to help reduce allergic reactions, are as follows:

  • Adults: 16 mg per kg of bodyweight
  • Children weighing over 40 kg: 16 mg per kg of bodyweight
  • Children weighing between 15 kg and 40 kg: 24 mg per kg of bodyweight
  • Children weighing less than 15 kg: 32 mg per kg of bodyweight

Because of the risk of allergic reaction, you will be monitored closely following the administration of this medication, in a facility with personnel and equipment suitable for dealing with anaphylaxis. If any symptoms of an allergic reaction arise, the medical staff will cease the infusion and treat these symptoms.


Some medications can interact with obiltoxaximab in ways that cause undesirable side effects. You should also inform your doctor of any medications that you are currently taking, as well as any over the counter products, vitamins and herbal supplements, because they will have access to the most up to date information in this regard.

The following medications are of particular concern:

  • Anthrax immune globulin human
  • BCG vaccine
  • Clostridium tetani toxoid antigen (formaldehyde inactivated)
  • Corynebacterium diphtheriae toxoid antigen (formaldehyde inactivated)
  • G17DT
  • GI-5005
  • Hepatitis A Vaccine
  • Hepatitis B Vaccine (Recombinant)
  • INGN 201
  • INGN 225
  • Rabies virus inactivated antigen, A
  • Rindopepimut
  • Rotavirus Vaccine
  • Rubella virus vaccine
  • Salmonella typhi ty21a live antigen
  • SRP 299
  • Tecemotide
  • TG4010
  • Varicella Zoster Vaccine (Live/Attenuated)
  • Yellow fever vaccine

The effectiveness of each of these medications may be reduced when they are taken at the same time as obiltoxaximab. This does not necessarily mean that you will be unable to take obiltoxaximab; however, the dosage of the medications may need to be altered, and your doctor may want to monitor you more closely during the time that you are being given obiltoxaximab.


Inform your doctor if you are allergic, or if you believe you may be allergic to obiltoxaximab, levofloxacin, ciprofloxacin or doxycycline.

Obiltoxaximab is usually given in conjunction with diphenhydramine, which is more commonly known under the brand name Benadryl. You should inform your doctor if you are allergic or have had any adverse reactions to diphenhydramine.

This medication should only be administered by trained medical professionals in a facility containing appropriate equipment for dealing with anaphylaxis.

When diphenhydramine is given at the same time as this medication, it may mask or delay the symptoms of an allergic reaction. For this reason, you would normally be kept under observation for some time after you have been given obiltoxaximab.

Inform the doctor in charge of your care of any existing medication conditions you suffer from before you are given this medication. Contact the nurse or doctor if the symptoms of your existing condition appear to get worse after the medication has been administered.

No adequate studies have been conducted to determine the impact of obiltoxaximab when taken by pregnant or breastfeeding women. The animal studies conducted to date appear to suggest that the drug is not passed to the unborn fetus. However, there is not enough data to say what happens when the drug is given to humans. Therefore, this medication would only be given to pregnant women when absolutely necessary.


To maintain the safety and potency of the medication, the following guidelines should be observed when storing obiltoxaximab:

  • Keep the medication refrigerated, at a temperature between 36 degrees and 46 degrees Fahrenheit (2 degrees to 8 degrees Celsius).
  • Do not freeze this medication.
  • Avoid exposure to direct sunlight and store obiltoxaximab in its original packaging, which will protect it from light.
  • Take care not to shake, drop or otherwise disturb the contents of the packaging.
  • Keep the medication away from sources of moisture or excess humidity.
  • Check the medication for signs of damage before use. The normal coloration should be between colorless and light yellow or light brown. It is normal to see some particulates in the solution.


Intravenous obiltoxaximab is an injection used to treat or prevent infection from the anthrax toxin. It works by interfering with the anthrax bacteria, preventing them from entering and destroying the cells in the body.

Although no human studies have been conducted testing the effectiveness of obiltoxaximab, several animal studies have shown improved survival rates against the anthrax bacteria, especially when obiltoxaximab is given alongside antibiotic drugs, such as levofloxacin, ciprofloxacin and doxycycline.

Although this medication has shown some effectiveness in helping to fight off an anthrax infection, it causes undesirable side effects in many people who take it. Although severe allergic reactions, such as anaphylaxis, are less common, they have been documented, so, for this reason, obiltoxaximab is only administered by or under close supervision of a doctor. It is not a medication that you would be prescribed and given to take by yourself at home.

Obiltoxaximab is usually given in combination with other medications, including antibiotics to help fight off the infection, and other medications that help reduce the risk of side effects.