Clinical efficacy and safety of clenbuterol HCl when administered to effect in horses with chronic obstructive pulmonary disease (COPD).

Abstract

A field study of 239 horses was conducted to determine the efficacy and safety of clenbuterol HCl, a beta 2-adrenergic bronchodilator, when administered incrementally to effect in the treatment of chronic obstructive pulmonary disease (COPD). The severity of COPD (heaves) and response to treatment was determined by clinical evaluation; an overall 'heaveiness rating' (OHR) was assigned at each observation. The horses were treated orally b.i.d. with clenbuterol (as Ventipulmin Syrup), beginning with the lowest dosage of 0.8 micrograms/kg. On day 10 of treatment at the effective dose (0.8, 1.6, 2.4 or 3.2 micrograms/kg), treatment was either withdrawn (Schedule A) or continued for an additional 20 days (Schedule B). Horses on Schedule A demonstrated a significant improvement in the mean OHR on treatment Day 10 compared to the baseline overall heaveiness rating (BOHR) and a significant increase in the mean OHR (relapse) after the drug was withdrawn. Schedule B horses showed significant improvement (compared to BOHR) on treatment Days 10, 20 and 30. Incremental dosing with clenbuterol provided clinical improvement in 75% of the horses with a lower 95% confidence limit of 71%. Twenty-five percent were nonresponders. A greater percentage of the more severely affected horses required the 3.2 micrograms/kg dosage or were nonresponders compared to horses with a lower BOHR. Side effects of sweating, muscle tremor, and nervousness were of low intensity (mild to moderate) and frequency (< 7% of all observations) due to the regimen of incremental dosing to effect.

• Authors: D F Erichsen, A D Aviad, R H Schultz, T J Kennedy
• Journal: Equine veterinary journal (Equine Vet J) Vol. 26 Issue 4 Pg. 331-6 (Jul 1994) ISSN: 0425-1644 [Print] United States
• PMID: 8575403 (Publication Type: Clinical Trial, Journal Article)

Chemical References

• Bronchodilator Agents
• Clenbuterol

Topics

• Animals
• Bronchodilator Agents (adverse effects, standards, therapeutic use)
• Clenbuterol (adverse effects, standards, therapeutic use)
• Dose-Response Relationship, Drug
• Female
• Horse Diseases (drug therapy)
• Horses
• Lung Diseases, Obstructive (drug therapy, veterinary)
• Male
• Time Factors
• Tremor (chemically induced, veterinary)