 The most common drug used for acute tocolysis is magnesium sulfate, which is administered intravenously to stop contractions8. While it appears to be effective for short-term tocolysis it is thought to be not as effective as anti-prostaglandins or calcium channel antagonists in quickly suppressing uterine activity. In addition, there has been controversy as to adverse effects on the neonate when this drug is used to impede uterine contractions9. Some authors feel that it causes adverse neurologic function in the baby where as others feel that it is not associated with any increase neonatal morbiditymortality in premature infants9.10. Regardless, for clinicians treating women in preterm labor magnesium remains the main stay of therapy. 