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Theophylline does not potentiate the effects of a low dose of dexamethasone in horses with recurrent airway obstruction
Author(s) -
CESARINI C.,
HAMILTON E.,
PICANDET V.,
LAVOIE J. P.
Publication year - 2006
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.2746/042516407x153048
Subject(s) - theophylline , dexamethasone , medicine , asthma , horse , crossover study , anesthesia , corticosteroid , exacerbation , pulmonary function testing , airway obstruction , airway , placebo , biology , pathology , paleontology , alternative medicine
Summary Reasons for performing study : Theophylline has been shown to have corticosteroid‐sparing effects for the treatment of human asthma. A similar effect, if present in horses, would allow diminishing the dose of corticosteroids administered to equine patients with inflammatory airway diseases. Objectives : To evaluate whether theophylline potentiates the effects of a low dose of dexamethasone when treating horses with recurrent airway obstruction (RAO). Hypothesis : Theophylline has steroid‐sparing effects in horses with RAO. Methods : Ten mature mixed breed horses in clinical exacerbation of RAO were studied. Using an incomplete crossover design and 3 experimental periods of 7 days duration, horses were distributed randomly in 5 treatment groups; and administered dexamethasone s.i.d., at either 0.05 mg/kg bwt i.v. or per os , or 0.02 mg/kg bwt alone or combined with theophylline at 5 mg/kg bwt per os b.i.d. A fifth group was treated with theophylline alone at the above dosage. Lung function was evaluated prior to drug administration and then 3 and 7 days later. Results : Oral administration of dexamethasone alone or combined with theophylline failed to improve lung function significantly in RAO affected horses. Theophylline alone also failed to improve lung function in all treated horses. Conversely, dexamethasone administration at 0.05 mg/kg bwt i.v. resulted in a significant improvement in lung function starting on Day 3. Conclusions and potential relevance : Oral theophylline for 7 days did not improve the effects of a low dose of dexamethasone for the treatment of horses with RAO.