Nifedipine (Adalat®) 10 mg sublingual crushed, then 10 mg sublingual in 15 min, followed by 10 mg PO Q 15 mins PRN to a maximum of 40 mg in the first hour. Maintenance of 60-80 mgs of slow-release nifedipine (Nifedicor®) daily for 48 hours (20 mg Q 8 hrs or 20 mg Q 6 hrs). Once contractions cease, nifedipine will be maintained at 60 mg daily in divided doses up to 36 weeks of gestation.