Antivenin

Company: Boehringer Ingelheim Animal Health

Crotalidae Polyvalent

(North and South American Snakebite Antiserum)

For use in animals only.

Restricted to use by or under the direction of a veterinarian.

Antivenin Indications

For use in dogs which have received bites from viperine snakes, such as rattlesnakes, copperheads and cottonmouth water moccasins. This product was licensed prior to the requirement to establish a minimum age for use.

Composition

Antivenin is a refined and concentrated preparation of equine serum globulins obtained by fractionating blood from healthy horses that have been immunized with the following venoms: Eastern diamondback (C. adamanteus), Western diamondback (C. atrox), Central and South American rattlesnake (C. terrificus) and fer-de-lance (B. atrox). Phenol (0.25%) and thimerosal (0.005%) (mercury derivative) are added as preservatives.

Antivenin neutralizes the venom of the viperine snakes, including all North American species of rattlesnakes, copperheads and cottonmouth moccasins. It contains a protective substance against the venoms of the related species in Central and South America, including the bushmaster and the fer-de-lance, and the habu and Mamushi of the Pacific Islands and Asiatic mainland.

Antivenin is standardized by its ability to neutralize in mice the toxic action of a standard venom injected intravenously.

Directions and dosage: Aseptically rehydrate the vaccine with the sterile diluent supplied. Administer 10 mL of rehydrated product intravenously.

The dose varies from 10 to 50 mL (1 to 5 vials), administered intravenously, of rehydrated Antivenin, depending on the severity of symptoms, lapse of time after the bite, size of snake and size of patient (the smaller the body of the victim, the larger the dose required). Additional doses should be given every 2 hours as required, if symptoms such as swelling and pain persist or recur.

In emergency, when exposure is such that intravenous administration is not practical, the product may be administered intramuscularly as close to the site of exposure as practical.

General supportive therapy should be instituted whenever required. The use of corticosteroids is controversial. Use professional discretion.

Precautions: Avoid freezing and excessive heat. Do not use in equine species. Storage temperature not to exceed 98°F (37°C). Use immediately after rehydration. Do not mix with other products, except as specified on the box. Use entire contents when first opened. In case of anaphylactoid reaction, administer epinephrine. This product has not been tested in pregnant animals. In case of human exposure, contact a physician. Inactivate unused contents before disposal.

Attempts should be made to immobilize the patient until treatment is initiated. The use of excessive heat or cold is contraindicated. Use antihistamines, tranquilizers, sedatives and analgesics with care because they may mask important clinical signs. Use professional discretion.

Sealed under partial vacuum.

General information: Antivenin is specific against the viperine class of snakes, whose venom is hemotoxic. The elapine are the second class of poisonous snakes and include the coral snake, the cobra, and the mamba. Their venom is mainly neurotoxic. Both classes of poisonous snakes contain some neurotoxic and hemotoxic factors. However, horses from which Antivenin is derived have not been immunized against elapine venom.

The death incidence, worldwide, from snake bite is greater in dogs than in any other domestic animal. They most frequently are bitten in the head region; occasionally on the shoulders, thighs or legs. Fatalities in horses and cattle are less common. However, they do occur, particularly when bitten about the head or neck.

Symptoms from viperine envenomation are swelling, pain, muscular weakness, impaired vision, cyanosis, hemolytic anemia, bleeding tendencies, dyspnea, shock and subsequent tissue necrosis.

Some clinical evaluators of Antivenin reported the diamondback as the most lethal snake to dogs, and the ground or pygmy rattler the least dangerous. Sloughing or tissue necrosis was most frequently associated with, but not limited to, the water moccasin.

Sixteen practicing veterinarians had uniformly successful results with Antivenin in patients having mild symptoms at time of treatment. Of 103 dogs treated with acute symptoms, 72% survived following a single 10 mL dose; there was a higher percentage (83%) of recovery when 20 to 70 mL was given. Overall, 82% of Antivenin-treated animals survived; the majority not receiving Antivenin succumbed. The success of Antivenin appears to be directly related to the time interval before treatment. Only 45% of dogs survived if there was at least a four-hour lag period between time of bite and Antivenin treatment. The survival rate doubled if less than four hours elapsed before Antivenin was administered.

Reference: Peterson, M. Snake Envenomation in Small Animal Critical Care Medicine by Silverstein, D.C. and Hopper, K. Saunebar Inc. 2009, pg 399-404.

Boehringer Ingelheim Animal Health USA Inc., St. Joseph, MO 64506

Phone: 1 (888) 637-4251

VLN/PCN 124/6101.00

CPN: 1028176.2