Effects of oral clenbuterol on the clinical and inflammatory response to endotoxaemia in the horse

Res Vet Sci. 2013 Jun;94(3):682-6. doi: 10.1016/j.rvsc.2013.01.003. Epub 2013 Feb 22.


Pro-inflammatory cytokines, such as IL-1β and TNFα, play a major role in activating leukocytes and endothelial cells during the systemic inflammatory response to endotoxin in the horse. β2 agonist drugs, such as clenbuterol, inhibit leukocyte activation. This study aimed to determine the effects of oral clenbuterol on clinical and leukocyte responses, including production of TNFα, in an in vivo endotoxin challenge model. In a randomised crossover design, horses received either clenbuterol or a placebo product prior to the administration of low dose endotoxin (30 ng/kg over 30 min). Clinical signs were measured and leukocyte counts and serial blood samples were obtained over 6 h. Pre-treatment with oral clenbuterol (0.8 μg/kg) significantly reduced (P=0.046) the peak rectal temperature and the peak plasma TNFα concentration (P=0.026) following endotoxin challenge. These data suggest that oral clenbuterol at the therapeutic dose has anti-inflammatory effects in horses challenged with a low dose of endotoxin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Animals
  • Anti-Inflammatory Agents / administration & dosage
  • Anti-Inflammatory Agents / therapeutic use*
  • Body Temperature / drug effects
  • Clenbuterol / administration & dosage
  • Clenbuterol / therapeutic use*
  • Endotoxemia / complications
  • Endotoxemia / drug therapy
  • Endotoxemia / veterinary*
  • Endotoxins / pharmacology
  • Female
  • Heart Rate / drug effects
  • Hematocrit / veterinary
  • Horse Diseases / drug therapy*
  • Horses
  • Inflammation / drug therapy
  • Inflammation / veterinary
  • Leukocyte Count / veterinary
  • Male
  • Respiratory Rate / drug effects
  • Tumor Necrosis Factor-alpha / blood


  • Anti-Inflammatory Agents
  • Endotoxins
  • Tumor Necrosis Factor-alpha
  • Clenbuterol