NCIt definition : A phenethylamine derivative with tocolytic activity. Ritodrine binds to and activates
beta-2 adrenergic receptors of myometrial cells in the uterus, which decreases the
intensity and frequency of uterine contractions. Specifically, ritodrine probably
activates adenyl cyclase, thereby increasing production of cyclic adenosine monophosphate
(cAMP), which in turn enhances the efflux of calcium from vascular smooth muscle cells.
A lack of intracellular calcium prevents uterine myometrial contractions. In addition,
this agent may directly inactivate myosin light chain kinase, a critical enzyme necessary
for the initiation of muscle contractions.;