title: Evaluation of efficacy of mineral oil, charcoal, and smectite in a rat model of equine cantharidin toxicosis.
abstract: BACKGROUND
  The efficacy of orally administered therapeutics for the treatment of cantharidin intoxication has not been evaluated in controlled studies.
  
  
  OBJECTIVE
  To develop a model of acute cantharidin intoxication in laboratory rats and to evaluate in this model the relative efficacy of 3 gastrointestinal therapies used to treat equine cantharidin toxicosis.
  
  
  METHODS
  Sixty-four male Sprague-Dawley rats.
  
  
  METHODS
  A blinded, randomized, controlled study was performed on rats surgically implanted with telemetry transmitters for evaluating heart rate, locomotor activity, and body temperature. Orogastric administration of cantharidin was performed within 15 seconds before administration of mineral oil, activated charcoal, or smectite. Negative control groups received therapeutic agents alone. Urine was collected for cantharidin analysis. Rats were sacrificed 24 hours after intoxication, and tissues were collected for histopathologic evaluation. Data analysis included ANOVA procedures and contingency tables.
  
  
  RESULTS
  Six of 8 cantharidin-intoxicated rats treated with mineral oil died; bradycardia and hypothermia developed in the animals of this group 0-8 hours after intoxication. Rats treated with mineral oil had higher urine cantharidin concentrations than rats receiving cantharidin alone or with smectite (P = .04). The most severe hypothermia (30.6°C ± 1.0) developed in rats administered mineral oil at 4-8 hours after intoxication, whereas those treated with charcoal (35.2°C ± 0.8) had mean body temperatures higher than all other treatment groups (P = .03). Survival times in the charcoal (P = .16) and smectite (P = .12) treatment groups were not statistically different from negative controls.
  
  
  CONCLUSIONS
  Mineral oil is often used in the treatment of equine cantharidin toxicosis. Our findings suggest that mineral oil increases cantharidin absorption, worsening morbidity and fatality in rats.
authors.affiliation: Weatherford Equine Medical Center, PC, Weatherford, TX.
authors.forename: H J
authors.initials: HJ
authors.lastname: Qualls
authors.forename: T C
authors.initials: TC
authors.lastname: Holbrook
authors.forename: L L
authors.initials: LL
authors.lastname: Gilliam
authors.forename: B L
authors.initials: BL
authors.lastname: Njaa
authors.forename: R J
authors.initials: RJ
authors.lastname: Panciera
authors.forename: C N
authors.initials: CN
authors.lastname: Pope
authors.forename: M E
authors.initials: ME
authors.lastname: Payton
mesh_terms: D000818:Animals; D000931:Antidotes / Q000627:therapeutic use*; D002193:Cantharidin / Q000633:toxicity*; D002606:Charcoal / Q000627:therapeutic use*; D004326:Drinking / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D008899:Mineral Oil / Q000627:therapeutic use*; D009043:Motor Activity / Q000187:drug effects; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D017640:Silicates / Q000627:therapeutic use*; D014554:Urination / Q000187:drug effects
chemical_list: D000931:Antidotes; D017640:Silicates; D002606:Charcoal; D008899:Mineral Oil; C033214:Smectite; D002193:Cantharidin
keywords: Biosponge; Charcoal; Mineral Oil; Smectite