Labor induction and augmentation with oxytocin: pharmacokinetic considerations.

Traditional protocols for oxytocin infusion regimens recommend increases of infusion rate at 15-20 min intervals. However recent clinical studies agree that prolonged intervals of 30-40 or even 60 minutes are superior to shorter dosage intervals in terms of safety and efficacy. These results are in good agreement with recent pharmacologic data on oxytocin in pregnant women, showing a half-life of about 15 minutes, and of current pharmacokinetic principles, which indicate that at least 3 half-lives of constant infusion will elapse before the corresponding clinical effect may be established. Increasing the oxytocin infusion earlier, could cause excessive uterine contractions and fetal distress.