Yesterday the U.S. Food and Drug Administration approved Anascorp, the first specific treatment for a scorpion sting by Centruroides scorpions in the United States.
In the U.S., most venomous scorpions are found in Arizona. There are 30 species of scorpions found there, buy only one is regarded as life-threatening: the Bark Scorpion (Centruroides exilicauda). It has slender tail segments and pincers, reaching only an inch and a half at maturity.
Scorpions are relatively inactive during the daylight hours. The majority of stings reported occur at night during the warm summer months.
Scorpion stings can cause immediate local pain with minimal swelling. Numbness and tingling are frequently reported. The injured area may be very sensitive to touch, pressure, heat and cold.
Small children are at highest risk of severe reactions which are marked by shortness of breath, fluid in the lungs, breathing problems, excess saliva, blurred vision, slurred speech, trouble swallowing, abnormal eye movements, muscle twitching, trouble walking, and other uncoordinated muscle movements. Untreated cases can be fatal.
“This product provides a new treatment for children and adults and is designed specifically for scorpion stings,” said Karen Midthun, M.D., director of the FDA’s Center for Biologics Evaluation and Research. “Scorpion stings can be life-threatening, especially in infants and children.”
Anascorp, Centruroides (Scorpion) Immune F(ab’)2 (Equine) Injection, is made from the plasma of horses immunized with scorpion venom. Anascorp may cause early or delayed allergic reactions in people sensitive to horse proteins. The manufacturing process for Anascorp includes steps to decrease the chance of allergic reactions and to reduce the risk of transmission of viruses that may be present in the plasma.
The effectiveness of Anascorp was based on results from a randomized, double-blind, placebo-controlled trial of 15 children with neurological signs of scorpion stings. These signs resolved within four hours of treatment in the eight subjects who received Anascorp, but in only one of the seven participants who received the placebo. The most common side effects were vomiting, fever, rash, nausea, itchiness, headache, runny nose, and muscle pain. In total, safety and efficacy data was collected from 1,534 patients in both open-label and blinded studies.
Anascorp was designated as an Orphan drug by FDA and received priority review. It is licensed to Rare Disease Therapeutics Inc., Franklin, TN, distributed by Accredo Health Group Inc., Memphis, TN, and manufactured by Instituto Bioclon, S.A. de C.V., of Tlalpan, Mexico, D.F.
Basic first aid steps if you are stung by any scorpion:
- Wash the area of the scorpion sting with soap and water.
- Apply a cool compress on the area of the scorpion sting.
- If stung on a limb (arm or leg) elevate the limb to heart level.
- If severe symptoms are present (these might include blurry vision, muscle twitching, roving eye movements, or other non-typical symptoms), go to the nearest emergency facility for treatment.
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