Antivenin (Micrurus Fulvius)

The immunizing agent Antivenin - Micrurus Fulvius is used to treat poisoning by North American Coral Snakes including the Eastern coral snake, Texas coral snake and other related species of coral snake.


Antivenin - Micrurus Fulvius is an immunizing agent effective against the venom of the North American coral snake. It is used for the treatment of poisoning from the bite of North American coral snakes including the Eastern and Texas coral snakes and other related species of coral snakes. It is not effective against bites from the Arizona or Sonoran coral snakes.

Coral snakes have the second strongest venom of any snake and the coral snake is considered to be one of the most toxic found in the North American region. The venom has powerful neurotoxins contained within it and can cause cardiac arrest if left untreated. Symptoms will take several hours to appear in humans and no deaths by coral snake have been reported since the development of antivenin. Symptoms of an untreated bite will include slurred speech, double vision and muscular paralysis.

The antivenin against coral snake venom is produced by immunizing horses with venom from the Eastern coral snake. The horse then develops antibodies against the poison and these are removed to create the antivenin. Antivenin Micrurus Fulvius should only be used under supervision of a doctor. It is available in pre-prepared kits and as a powder or solution.

Children have been shown to tolerate receiving North American coral snake antivenin better than adults. Reactions to a bite, however, can be more severe because of the ratio of venom to body weight. Children may therefore need to be given a higher dose of North American coral snake antivenin than adults.

Serum sickness can occur in the patient for up to 24 days after receiving the antivenin. This occurs when the body mistakenly attacks the antibodies in the blood stream. Serum sickness is rare but can be serious so any symptoms in the weeks after receiving the antivenin should be reported to your doctor.

Condition treated

  • Poisoning by Coral Snake

Type of medicine

  • Immunizing agent
  • Anti-venom

Side Effects

Along with neutralizing the venom in your bloodstream, Antivenin Micrurus Fulvius can cause unwanted side effects in the body. In some cases these side effects will require medical attention. Other side effects will not require medical attention but should be reported to your doctor if they are ongoing or bothersome.

If you experience any of the following side effects then you should seek medical attention immediately:

  • Difficulty breathing
  • Difficulty swallowing
  • Hives
  • Itching of the feet
  • Itching of the hands
  • Reddening of the skin. This is particularly significant around the ears.
  • Swelling of the eyes
  • Swelling of the face
  • Swelling of the inside of the nose
  • Unusual tiredness
  • Unusual weakness
  • Uticaria
  • Vomiting
  • Wheezing
  • Serum sickness

Serum sickness can occur in patients who have received the North American antivenin for up to 24 days after receiving it. Symptoms can occur at any time in this 24 day period. Serum sickness is a reaction similar to an allergy and is caused when the body falsely recognizes the antibodies in the antivenin as harmful and begins attacking them.

Symptoms of serum sickness include:

These symptoms can occur for up to 24 days and should be reported to a medical professional if they do.

Other side effects not listed herein may occur. If they do you should report them to a medical professional and seek advice.


The dose of this medicine will differ depending on each patient. Follow the instructions given by your doctor and always read the label.

Dosing will depend on age, body size and amount of venom in the body. It will also depend on the strength of the medicine that you are taking.

Tell your doctor if you are on any kind of diet as certain diets can affect the effectiveness of the medication.

Before receiving a dose of antivenin you will receive a skin test injected intradermally. You will be observed for 20 minutes for adverse reactions before being given a full dose. The full dose will be administered in increasing increments until the desired effect has been achieved.

The antivenin is administered in vials. An individual vial must be mixed to a 10-mL solution before it can be used. Initial therapy should consist of the administering of 3-5 vials with the initial 1 to 2 mL given over 3-5 minutes. As the patient shows that they are able to tolerate the dose the rate at which it is given can be increased.

When required additional doses can be given by the doctor. This medicine should only be administered under supervision of a doctor.


Before taking any medicine you should weigh the good that it will do against the risks of taking the medication. For this medicine you will need to consider the following:

Allergies - If you have any allergies to or have had any unusual reactions to medicines then you should tell your doctor before you receive the antivenin. Tell the doctor of any allergies you have to foods, dyes, preservatives or animals. As antivenin Micrurus Fulvius is made by immunizing horses it is vitally important that you tell your doctor if you have an allergy to horses. In extreme cases anaphylaxis (a severe allergic reaction) can occur. This will occur within the first 30 minutes of medication being administered.

Breastfeeding - There is no sufficient information regarding breastfeeding and the risk to infants whilst taking this medicine. Before breastfeeding, weigh the benefits against the potential risks while taking this medication.

Drug interactions - Interactions between medicines can occur. Before taking this medicine you should inform your doctor of all medication that you are taking. Your doctor may take precautions depending on the prescription or non-prescription medication that you are taking.

Consumables - Certain medicines can interact with foods, drinks and tobacco or alcohol. Discuss your use of tobacco and alcohol with your healthcare professional and ask about the foods and drinks that you will be consuming.


Beware of anaphylaxis. This severe allergic reaction can occur in very rare cases. The incremental dosing will highlight this before significant doses are given but a doctor should always be on hand for emergencies.

Do not give contaminated individual morphine or strong sedatives. As sedatives can affect the blood pressure and heartrate they can increase the risk of cardiac arrest from the venom.

Antivenin Micrurus Fulvius will not neutralize venom from the Arizona or Sonoran coral snakes.

Always inform your doctor of any underlying medical problems before receiving treatment. In some cases medicines can make certain conditions worse so it is vital that you share this information. This is particularly important if you have any existing issues of the heart, liver or kidneys.


Refrigerate unopened vials.

Do not allow medicine to freeze.

Always ensure that you dispose of expired medicine appropriately following the correct procedures.

Opened vials should not be stored. Dispose of all open vials and administration equipment appropriately.

Do not keep out of date medicines. Dispose of these appropriately.


Antivenin Micrurus Fulvius is used to counteract poisoning by the North American coral snake. While bites are rarely fatal following the advent of the antivenin, the coral snake is the second most toxic snake on the planet.

Untreated bites can lead to cardiac arrest after several hours. Symptoms experienced before this will include slurring, muscle paralysis and double vision.

The antivenin is made by immunizing horses against the North American coral snake. The antivenin is then injected into the patient in incremental doses.

In very rare cases anaphylaxis can occur so the patient is given a reaction test before dosing begins. Allergies to horses could make this antivenin unsuitable for you.

Serum sickness can occur after receiving the antivenin and symptoms can appear up to 24 days after the treatment is given to the patient. Serum sickness occurs when the body incorrectly identifies the antivenin as harmful and begins attacking it. If the symptoms of serum sickness are experienced in a 24 day period medical attention should be sought.

Children have been shown to have a higher tolerance for antivenin Micrurus Fulvius. As a bite will lead to a greater venom blood ratio in a child they do, however, often need to receive a higher dose of the antivenin to counteract the effects of the bite and the venom.

Last Reviewed:
December 23, 2017
Last Updated:
April 02, 2018