A pilot study comparing the antispasmodic effects of inhaled salmeterol, salbutamol and ipratropium bromide using different aerosol devices on muscarinic bronchoconstriction in healthy cats.
This study compared the duration and magnitude of the antispasmodic effects of salmeterol (SLM), salbutamol (SAL), ipratropium bromide (IB) and the combination of SAL and IB (SAL/IB) against carbachol-induced bronchoconstriction in healthy cats, and investigated the gain in efficacy using a two or fourfold increase in drug dosages. The drug regimens used were: (1) SLM 25 microg, SAL 100 microg, IB 20 microg and SAL/IB 100 microg/20 microg for bronchodilators delivered by a metered-dose inhaler (MDI); (2) SAL 3.75 mg and IB 62.5 microg for nebulised (NEB) medications. To monitor the bronchodilator effect, airway responsiveness was assessed at different time points using barometric whole-body plethysmography and calculation of the concentration of inhaled carbachol inducing a 300% increase of baseline Penh (enhanced pause), an estimator of airflow limitation. Maximum C-Penh300 was recorded 15 min after NEB SAL, IB MDI, NEB IB and 1h after SAL MDI and 4h after SLM MDI, respectively. C-Penh300 was significantly different from control values (without treatment) up to 24h for SLM MDI, 8h for IB MDI and 4h for other drugs. In terms of efficacy, SAL/IB MDI showed a synergistic antispasmodic effect at 15 min, 4h and 8h after administration. A fourfold increase of the initial dose of IB MDI and NEB IB significantly increased C-Penh300. Despite a fourfold dose increase, SLM displayed the weakest degree of bronchoprotection compared to other bronchodilators. The study provides evidence that inhaled bronchodilators are efficient at preventing muscarinic-induced bronchospasm in healthy cats and that SAL and IB appear to be short-acting bronchodilators in contrast to SLM.
Leemans
Jérôme
J
Section of Pharmacology, Pharmacotherapy and Toxicology, Department for Functional Sciences B41, Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium.
Kirschvink
Nathalie
N
Bernaerts
Frédérique
F
Clercx
Cécile
C
Cambier
Carole
C
Gustin
Pascal
P
D000280:Administration, Inhalation; D000420:Albuterol / Q000008:administration & dosage / Q000031:analogs & derivatives; D000818:Animals; D016084:Bronchoconstriction / Q000187:drug effects*; D001993:Bronchodilator Agents / Q000008:administration & dosage*; D002415:Cats / Q000502:physiology*; D005260:Female; D009241:Ipratropium / Q000008:administration & dosage; D008297:Male; D036501:Metered Dose Inhalers / Q000662:veterinary; D010865:Pilot Projects; D010993:Plethysmography, Whole Body / Q000662:veterinary; D000068299:Salmeterol Xinafoate
D001993:Bronchodilator Agents; D000068299:Salmeterol Xinafoate; D009241:Ipratropium; D000420:Albuterol