Related Experiment Videos
Anticholinergic blockade of beta-blocker-induced bronchoconstriction
P W Ind1, C M Dixon, R W Fuller
1Department of Medicine, Royal Postgraduate Medical School, London, United Kingdom.
The American Review of Respiratory Disease
|June 1, 1989
Summary
Propranolol causes bronchoconstriction in asthma patients, but oxitropium bromide, an anticholinergic agent, completely blocks this effect. This suggests that cholinergic mechanisms are involved in propranolol-induced bronchoconstriction (PIB).
Area of Science:
- Pulmonary Medicine
- Pharmacology
- Respiratory Physiology
Background:
- The mechanism of propranolol-induced bronchoconstriction (PIB) in asthma is not fully understood.
- Prior studies suggest atropine may counteract PIB in asthmatic individuals.
Purpose of the Study:
- To investigate the effect of the anticholinergic agent oxitropium bromide on propranolol-induced bronchoconstriction (PIB) in mild asthma.
- To explore the role of cholinergic mechanisms in PIB.
Main Methods:
- A randomized, double-blind, placebo-controlled study involving seven mild asthma subjects (24-39 years).
- Inhaled propranolol was administered to induce bronchoconstriction, measured by specific airway conductance (SGaw).
- Subjects were pretreated with oxitropium bromide (200 micrograms) or placebo.
Main Results:
- Inhaled propranolol induced prolonged reduction in SGaw in all subjects, indicating beta-adrenoceptor blockade.
- Oxitropium bromide pretreatment completely prevented the fall in SGaw caused by inhaled propranolol.
- Oxitropium also unmasked PIB, suggesting its involvement.
Conclusions:
- Cholinergic receptor blockade by oxitropium bromide inhibits propranolol-induced bronchoconstriction (PIB).
- These findings support the involvement of cholinergic mechanisms in the development of PIB.
- Anticholinergic agents may be beneficial in managing PIB.