Single dosing comparison of the relative cardiac beta 1/beta 2 activity of inhaled fenoterol and salbutamol in normal subjects.

D M Newnham, N M Wheeldon, B J Lipworth, D G McDevitt

Department of Clinical Pharmacology, Ninewells Hospital and Medical School, Dundee.

BACKGROUND--The aim of the present study was to compare the dose related effects of fenoterol and salbutamol on cardiac beta 1 and beta 2 receptors using the beta 1 selective antagonist atenolol, in order to dissect out relative beta 1/beta 2 mediated responses. METHODS--Fourteen normal volunteers were randomised to receive pretreatment with either atenolol 25 mg or placebo, followed by inhaled fenoterol or salbutamol in equal doses by weight (cumulative doses of 1 mg and 4 mg). Measurements were made 30 minutes after inhaling each dose of beta 2 agonist. Values (mean and 95% CI) were expressed as a change from baseline. RESULTS--At 4 mg fenoterol produced equivalent falls in serum potassium and increases in tremor to salbutamol. The mean (95% CI) increase in heart rate (beats/min) with fenoterol at 4 mg after placebo was 47 (41-53) and after atenolol was 34 (28-40), with values for salbutamol being 46 (40-52) after placebo and 30 (24-36) after atenolol. The inotropic response (stroke distance) after atenolol at the 4 mg dose was 5.0 (3.9-6.1) cm for fenoterol and 4.7 (3.5-5.9) cm for salbutamol. There were no significant differences in heart rate or stroke distance response between the two drugs after either placebo or atenolol. Furthermore, ECG effects (Q-Tc and T wave) of fenoterol and salbutamol were comparable at both doses. CONCLUSIONS--These results show that there is no difference in the respective chronotropic or inotropic activities of fenoterol and salbutamol on cardiac beta 1 or beta 2 receptors when given at higher than conventional doses.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

Relevant Article

Extrapulmonary effects of fenoterol and salbutamol in normal subjects.

J Crane, C Burgess, R Beasley, and C Wong
Thorax 1994 49: 191. [PDF]

This article has been cited by other articles:

• Weiner, P., Berar-Yanay, N., Davidovich, A., Magadle, R. (1999). Nocturnal Cortisol Secretion in Asthmatic Patients After Inhalation of Fluticasone Propionate. Chest 116: 931-934 [Abstract] [Full Text]  
• DHAND, R., GOODE, M., REID, R., FINK, J. B., FAHEY, P. J., TOBIN, M. J. (1999). Preferential Pulmonary Retention of (S)-Albuterol after Inhalation of Racemic Albuterol. Am. J. Respir. Crit. Care Med. 160: 1136-1141 [Abstract] [Full Text]