Epsilon Archive for Student Projects

Abstract

Bronchiolitis is a common performance decreasing disease in horses (Bracher et al,
1991¸Dixon et al, 1995) Its medical treatment includes inhalation therapy with
corticosteroids and b2-adrenoceptorer stimulators. Use of both these medicines is
prohibited for sport horses and athletes. Because the facemasks used for inhalation
therapy are not airtight, there is a risk for leakage of these medicines. We wanted to
see if cross exposure of nearby horses can result during normal recommended
treatment of a horse, and assess if this could result in doping positive urine sample
from the person treating the horse and from horses in the same airspace.
We did a pilot study with four healthy horses. The experiment was divided into
four parts. Two of them were done with corticosteroids and two with b2-
adrenoceptor stimulators. Both medicines were tested separately with the two
different metered dosed inhalers that are most commonly used in Sweden. In each
experiment one of the horses was treated while standing in the stable with the three
other horses, following which urine samples were collected from all four horses as
well as from the person administering the treatment. Due to economic constraints
only samples from the b2-adrenoceptor stimulator experiments were analysed.
Following inhalation treatment of a horse using either inhalation mask,
detectable levels of b2-adrenoceptor stimulator were measurable on some occasions
in the urine of some of the untreated horses and in the person administering the
drug. The threshold for doping value of b2-adrenoceptor stimulator in humans
was not exceeded in this study. For horses there is a specific doping concentration
value for corticosteroids but none for b2-adrenoceptors. This means that if it is
possible to detect b2-adrenoceptors in a urine sample, no matter at which
concentration, it would be considered doping positive. The results of this study
suggest that there is leakage from the inhalation masks sufficient to expose both
the person treating the horse, and neighbouring, untreated horses to inhaled
medications.