Cantharidin
Cantharidin, a type of terpenoid, is a poisonous chemical compound secreted by many species of blister beetle, and most notably by the Spanish fly, Lytta vesicatoria. The false blister beetles and cardinal beetles also have cantharidin.
Contents
History
Cantharidin was first isolated by Pierre Robiquet in 1810. It is an odorless and colorless solid at room temperature. It is secreted by the male blister beetle and given to the female during the mating. Afterwards the female beetle will cover its eggs with it as a defense against predators. The complete mechanism of the biosynthesis is currently unknown. If cantharidin is ingested, it severely irritates the urinary tract as it is excreted, causing swelling of the genitalia. This can cause a harmful condition known as priapism in men, where an erection lasts more than about four hours.
Medical uses
Diluted, it can be used to remove warts[1] and tattoos and to treat the small papules of Molluscum contagiosum.[2]
Medical risks for humans
Its potential for adverse effects has led it to being included in a list of "problem drugs" used by dermatologists.[3]
When ingested by humans, the LD50 is around 0.5 mg/kg, with a dose of as little as 10 milligrams being potentially fatal. Ingesting cantharidin can also cause permanent renal damage. Symptoms of cantharidin poisoning include haematuria and abdominal pains.
The extreme toxicity of cantharidin makes any use as an aphrodisiac highly dangerous because it can easily cause death. As a result, it is illegal to sell (or use) cantharidin for this purpose in many countries.
Medical risks for animals
Horses are highly sensitive to cantharidin: the LD50 for horses is approximately 1 mg/kg of the horse's body weight. Horses may be accidentally poisoned when fed bales of fodder with blister beetles in them.[1]
Footnotes
- ^ Epstein WL, Kligman AM (1958). "Treatment of warts with cantharidin". A. M. A. archives of dermatology 77 (5): 508–11. PMID 13519856.
- ^ "Molluscum contagiosum". Merck Manuals. November 2005. http://www.merck.com/mmpe/sec10/ch122/ch122b.html. Retrieved on 2007-10-21.
- ^ Binder R (1979). "Malpractice--in dermatology". Cutis; cutaneous medicine for the practitioner 23 (5): 663–6. PMID 456036.