Which medication is considered a systemic Beta-2 agonist?

Levalbuterol is considered a systemic Beta-2 agonist because it specifically targets the beta-2 adrenergic receptors, which are primarily found in the smooth muscles of the airways. This action leads to bronchodilation, making it effective for treating conditions such as asthma and chronic obstructive pulmonary disease (COPD). Levalbuterol is an isomer of albuterol that has been formulated to provide fewer side effects while still effectively relaxing bronchial smooth muscle.

In systemic use, it can influence respiratory function throughout the body, not just locally within the lungs. This allows for a broader therapeutic effect in managing respiratory distress compared to medications that do not have a similar selective action on beta-2 receptors.

Other medications listed have different mechanisms and primary uses. Dopamine is a precursor of norepinephrine and generally affects dopamine receptors and alpha/beta adrenergic receptors, but it is not primarily used for a beta-2 agonistic effect. Pergolide is a dopamine agonist used in the treatment of Parkinson's disease and does not act on beta-2 receptors. Atenolol is a selective beta-1 blocker primarily used for cardiovascular conditions and does not exhibit beta-2 agonist activity. Therefore, among the choices, leval