| Magnesium sulfate | Intracellular calcium antagonism | 4 to 6 g loading dose; then 2 to 4 g IV every hour |
| Terbutaline (Bricanyl) | Beta2-adrenergic receptor agonist sympathomimetic; decreases free intracellular calcium ions | 0.25 to 0.5 mg SC every three to four hours |
| Ritodrine (Yutopar) | Same as terbutaline | 0.05 to 0.35 mg per minute IV |
| Nifedipine (Procardia) | Calcium channel blocker | 5 to 10 mg SL every 15 to 20 minutes (up to four times), then 10 to 20 mg orally every four to six hours |
| Indomethacin (Indocin) | Prostaglandin inhibitor | 50- to 100-mg rectal suppository, then 25 to 50 mg orally every six hours |