When caring for a client with an upper respiratory infection (URI), the nurse is notified the client is taking guaifenesin (Mucinex). What is the mechanism of action of guaifenesin (Mucinex)?

Stimulate alpha-adrenergic receptors, thus producing vascular constriction of capillaries in nasal mucosa

Compete with histamine for receptor sites, thus preventing a histamine response and overall congestion.

Treat allergic rhinitis and prevent motion sickness.

Loosen bronchial secretion to assist in elimination.