Pryde Peter G, Mittendorf Robert
From The University of Wisconsin Medical School, Madison, Wisconsin; and the Departments of Obstetrics and Gynecology and of Pediatrics, Loyola University Medical Center, Maywood, Illinois.
Obstet Gynecol. 2009 Sep;114(3):669-673. doi: 10.1097/AOG.0b013e3181b43b0e.
Magnesium sulfate, a biologically potent compound, given sometimes in extraordinarily high doses, is among the most commonly used pharmaceuticals in American obstetric practice. Although most clinicians are in accord regarding its value for seizure prophylaxis in the setting of preeclampsia, such unanimity is not the case regarding its role in preterm labor. Credible scientific data indicate not only a lack of efficacy, but also toxicity to susceptible fetuses when magnesium sulfate is used in the high dosages found in tocolysis. In apparent contrast, three recent clinical trials, although individually inconclusive, provide data from which a very recent meta-analysis affirms a potential role for magnesium sulfate in prophylaxis against fetal neurologic injury. Comparing outcomes from these trials, with attention to dosage, relationships are revealed that unify observations previously regarded as conflicting: Magnesium sulfate indeed may have both neuroprotective and fetal toxic effects. The better, and safer, neuroprotection seems to occur at comparatively low antenatal doses (perhaps in a range between 4 g and 10.5 g), whereas increasing dosages exceed a "therapeutic window" whereby, as with most drugs, toxic sequelae begin to accrue.
硫酸镁是一种具有生物活性的化合物，有时会以极高的剂量使用，它是美国产科实践中最常用的药物之一。尽管大多数临床医生对于其在子痫前期预防癫痫发作方面的价值达成了共识，但在其在早产中的作用方面并非如此。可靠的科学数据表明，硫酸镁在用于宫缩抑制时所采用的高剂量不仅缺乏疗效，而且对易受影响的胎儿有毒性。明显相反的是，最近的三项临床试验虽然各自都没有定论，但提供的数据使得一项最新的荟萃分析证实了硫酸镁在预防胎儿神经损伤方面的潜在作用。比较这些试验的结果，并关注剂量，可以发现一些关系，这些关系将以前被认为相互矛盾的观察结果统一了起来：硫酸镁确实可能同时具有神经保护作用和胎儿毒性作用。更好且更安全的神经保护作用似乎发生在相对较低的产前剂量（可能在4克至10.5克之间），而随着剂量增加超过一个“治疗窗口”，与大多数药物一样，毒性后遗症开始出现。
