Ritodrine is a β2-AR (β2-adrenoceptor) agonist that acts as an adrenergic receptor stimulant. gives priority to act on the adrenergic receptors on the uterine smooth muscle through membrane-mediated effects of uterine smooth muscle cells, and uterine smooth muscle cells β2-AR (β2-adrenoceptor). Which activates cell membrane adenylate cyclase to adenosine triphosphate into cyclic adenosine monophosphate (cAMP), leading to increased intracellular cAMP, thus reducing myosin light chain kinase activity in reducing intracellular calcium concentration at the same time.