magnesium sulfate + terbutaline

Magnesium sulfate + terbutaline is a combination of two drugs used primarily as tocolytic agents to suppress preterm labor. Magnesium sulfate acts as a calcium antagonist, reducing uterine muscle contractility by interfering with calcium uptake in smooth muscle cells. Terbutaline is a selective beta-2 adrenergic receptor agonist that relaxes uterine and bronchial smooth muscle by increasing intracellular cyclic AMP, leading to decreased intracellular calcium and subsequent smooth muscle relaxation. The combination has been studied for its potential synergistic effect in delaying preterm birth, though the safety and efficacy of long-term use remain under investigation[1][2][7][9]. Both agents are also used individually for other indications—magnesium sulfate for eclampsia/seizure prophylaxis and terbutaline for asthma/bronchospasm—but their combined use is mainly explored in obstetric settings.