Snapshot A 24-year-old G1P0 presents to a local emergency room with contractions. She is currently 30 weeks pregnant. She reports her membranes have not ruptured. She is given a tocolytic to suppress the contractions. She is also given betamethasone to promote fetal lung maturity. She is transferred to a larger tertiary care center. Introduction Drugs tocolytics are medications that cause uterine relaxation terbutaline nifedipine indomethacin Mechanism of action terbutaline β2 agonists nifedipine calcium channel blocker indomethacin nonsteroidal anti-inflammatory drugs Clinical use decrease contraction frequency in patients with preterm labor allows time for steroid administration to optimize fetal lung maturity Adverse effects terbutaline restlessness tachycardia nifedipine peripheral edema flushing and dizziness indomethacin gastric ulcer nephrotoxic