Can Benadryl Treat Rattlesnake Bites?

Some people in “Rattlesnake Country” claim antihistamines can treat venomous snakebites.

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Claim

The common allergy drug Benadryl can be used to treat rattlesnake bites.

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Origin

A Facebook post shared in July 2019 claimed that the over-the-counter allergy drug Benadryl could be used to treat a rattlesnake bite. Since its original posting, the status has received more than 12,000 shares:

Benadryl might save a life: For anyone in Rattlesnake country: I have learned something new that I thought was important enough that I wanted to pass on. A man was bitten by a rattlesnake a few days ago. He was getting ready to bale and turned over a windrow to check the moisture and the snake was in it.

It wrapped around his arm and bit him on the underside of the wrist. Luckily it was not a severe bite, the fang marks were clear, but not deep enough to draw blood.

He came straight to the house and we got ice on it and had him to the hospital within an hour.

I called ahead so the emergency room was ready for him.

By the time he got there his arm was starting to swell to the shoulder and his throat was getting tight.

The first thing the emergency room did was give him Benadryl.

Apparently antivenom must be received within 4 hours of the snakebite, but the immediate threat is swelling and death of tissue, which was treated with the Benadryl.

But there is no truth to this claim, according to an international group of doctors, paramedics, and scientists collectively known as the Snakebite Foundation.

“Benadryl is not effective for snake envenomations in humans or other animals. Please stop sharing this information. Antivenom along with proper supportive care are the only effective treatments supported by peer-reviewed literature,” wrote Snakebite Foundation member Dr. Nick Brandehoff, an emergency physician and medical toxicologist at the University of California, San Francisco at Fresno, in a blog post.

Rattlesnake venom is made up of a variety of peptides and proteins described in the scientific journal Chemical Ecology as a “multifunctional cocktail” that, once injected into the bloodstream, can cause harmful neurotoxic and inflammatory issues. In particular, rattlesnake venom contains two neurotoxins that can lead to pain, paralysis, tissue necrosis, and in extreme cases death.

To treat bites from pit vipers and other venomous snakes, the World Health Organization strictly advises the use of antivenoms, which work by boosting a patient’s immune response. Antivenoms are produced by harvesting snake venom and then using it to immunize donor animals such as horses and sheep. Antibodies from these animals are then harvested and purified from plasma that can “literally make a difference between life and death.”

An allergy, on the other hand, is an immune response to allergens that releases chemicals known as histamines. These are treated with antihistamines like Benadryl, more commonly known as diphenhydramine, according to the U.S. National Library of Medicine. In some cases, American Family Physician notes that antihistamines may be used to treat anaphylaxis, which the Journal of Wilderness Medicine reports has been known to result from a rattlesnake bite, in conjunction with epinephrine.

“Comparing bee venom and snake venom to assume Benadryl will work is not congruent. Bee venom specially targets cells causing [the] release of histamine which results in swelling, pain, redness, and allergic reactions. This is similar to the pathway for non-venom induced allergic reactions,” wrote Brandehoff, highlighting that snake venom works “via different mechanisms.”

In the event of a rattlesnake bite, the Centers for Disease Control and Prevention recommends seeking medical attention as soon as possible. 

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Sources

Brandehoff, Nick.   “Benadryl Does Not Fix Snakebites.”
    Snakebite Foundation Blog.   3 July 2019.

Ferraz, Camila, et al.   “Multifunctional Toxins in Snake Venoms and Therapeutic Implications: From Pain to Hemorrhaging and Necrosis.”
    Chemical Ecology.   19 June 2019 &nbsp.

Patel, Virat, Hamilton, Richard.   “Rattlesnake Toxicity.”
    StatPearls .   4 June 2020 &nbsp.

Tang, Angela.   “A Practical Guide to Anaphylaxis.”
    American Family Physician.   1 Oct 2003 &nbsp.

Ryan, Kenneth, Caravati, Martin. “Life-threatening anaphylaxis following envenomation by two different species of Crotalidae.”
    Journal of Wilderness Medicine.   1994 &nbsp.