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Table 6-2

Indomethacin and Nifedipine Tocolytic Overview

DrugMechanism of ActionDosing RegimenContraindicationsSide EffectsNotes
IndomethacinProstaglandin synthetase inhibitor: prevents production of prostaglandin F2α, which normally stimulates uterine contractions

  • Loading dose: 50-100 mg orally or per rectum

  • Maintenance dose: 35-50 mg orally or per rectum every 4 h for 72 h

  • Peptic ulcer disease

  • Renal disease

  • Hepatic dysfunction

  • Coagulopathy

  • Oligohydramnios

  • Oligohydramnios

  • Nausea

  • GERD/gastritis

  • Emesis

  • Platelet dysfunction (rare)

  • First-line agent in gestations <32 wk

  • Avoid at >32 wk gestation (associated with premature closure of fetal ductus arteriosus).

  • Avoid using for >72 h (associated with oligohydramnios).

NifedipineCalcium channel blocker: inhibits myometrial calcium entry10-20 mg orally every 6 h

  • Hypotension

  • Congestive heart failure

  • Aortic stenosis

  • Hypotension

  • Flushing

  • Light-headedness

  • Dizziness

  • Nausea

First-line agent

Abbreviation: GERD, gastroesophageal reflux disease.