What medication is classified as a tocolytic agent?

Tocolytic agents are medications used to suppress premature labor by inhibiting uterine contractions. Among the options, terbutaline is categorized as a tocolytic because it is a beta-adrenergic agonist that relaxes smooth muscle in the uterus, thereby reducing uterine contractions. This effect can help delay preterm labor, allowing time for fetal development or for other interventions.

Though magnesium sulfate is also used in obstetric settings, its primary purpose is to prevent seizures in women with preeclampsia or eclampsia. Nifedipine, which is a calcium channel blocker, can act as a tocolytic as well, but terbutaline is more commonly recognized specifically in that role. Oxytocin, on the other hand, is used to induce labor rather than to suppress it. Therefore, terbutaline is the most appropriate choice when identifying a medication classified directly as a tocolytic agent.