Which medication is recommended for promoting bronchodilation when a patient is unresponsive to beta-agonist treatments?

Aminophylline is a xanthine derivative that acts as a bronchodilator and is often used in cases where patients show insufficient response to beta-agonist treatments. When beta-agonists, which stimulate the sympathetic nervous system to relax bronchial smooth muscles, fail to provide adequate bronchodilation, aminophylline can be employed as an alternative. It works through phosphodiesterase inhibition, leading to increased levels of cyclic AMP, which further promotes bronchodilation.

This option offers a different mechanism of action than beta-agonists, which can be crucial for patients whose condition is unresponsive to conventional therapy. In those situations, aminophylline may help improve airflow and alleviate symptoms by relaxing the bronchial smooth muscles, thus providing an additional tool in the management of acute bronchospasm.

Other medications listed, while all having important roles in respiratory therapy, are primarily beta-agonists or bronchodilators with different characteristics. Therefore, they may not provide the necessary alternative therapy when beta-agonists alone are ineffective.