tiotropium + long-acting beta-agonist

**Tiotropium + long-acting beta-agonist** is a combination of two classes of inhaled bronchodilators used primarily for the maintenance treatment of chronic obstructive pulmonary disease (COPD). Tiotropium is a long-acting muscarinic antagonist (LAMA) that blocks muscarinic acetylcholine receptors (mainly M1 and M3) in the airway smooth muscle, inducing bronchodilation by inhibiting acetylcholine-mediated bronchoconstriction. Long-acting beta-agonists (LABAs) are a class of drugs that stimulate beta-2 adrenergic receptors on airway smooth muscle, leading to activation of adenylyl cyclase, increased intracellular cAMP, and subsequent relaxation of airway smooth muscle. The combination offers additive bronchodilation by targeting different but complementary pathways, improving lung function and quality of life to a greater extent than either drug class alone. This combination does not refer to a single branded product but to co-administration of these drug classes, often using inhalers containing tiotropium with a separately administered LABA (e.g., salmeterol, formoterol, indacaterol). The main indication is for COPD maintenance therapy in patients whose symptoms are not adequately controlled by a single bronchodilator[1][3][5].