Efficacy and tolerance study of acetylcysteine in the COB/COPD therapy in horses

The efficacy and the tolerance of acetylcysteine was tested in forty horses suffering from chronic obstructive pulmonary disease (COPD). For an applic ation period of twenty days the horses were treated with daily oral doses o f 10 mg/kg, 20 mg/kg body weight acetylcysteine or with a placebo. The tota l amount of placebo or acetylcysteine was given twice daily with the concen trated feed. The clinical trial was conducted as an randomised double blind study. In the first group 15 horses were treated with acetylcysteine 2 x 5 mg/kg bw, in a second group of 15 horses acetylcysteine was given at a dos e of 2 x 10 mg/kg bw. A third group of 10 horses just received a placebo. V arious clinical parameters were detected as fluidisation and reduction of t he bronchial secretion, as well as blood gas analysis and secretory cytolog y for examining the efficacy of acetylcysteine. In this study we could show the bronchosecretolytic efficacy of acetylcysteine. Best results were obta ined with acetylcysteine in the daily dose of 20 mg/kg bw in respect of the primary parameter "viscosity" (80 % success rate after 20 days of treatmen t with acetylcysteine), whereas just 60 per cent of the horses improved in the group treated with 10 mg/kg bw. In respect to the secondary parameter " volume of secretion" the group treated with 10 mg/kg acetylcysteine showed lower secretion volume than the group of horses medicated with 20 mg/kg ace tylcysteine or the group receiving placebo. During the 20 days of therapy n one of the horses showed any problems concerning the palatability or the di gestibility. The study identified neither any rejection or adverse affects after any of the three treatments nor did the laboratory examination of blo od show any deviations from normal values. This tolerance and efficacy stud y of acetylcysteine in horses showed an adequate tin the group received 10 mg/kg body weight) or good tin the group received 20 mg/kg body weight) muc olytic effect on the viscous tracheobronchial secretion. Hence in the treat ment of equine chronic pulmonary disease a daily dose of 20 mg/kg bw should be recommended. The treatment period should be at least two weeks. Better mucolytic results will be obtained when acetylcysteine is given for several weeks. Therapy of horses suffered by COPD will be improved by NAC medicati on.