Anti-Infective and Anti-Inflammatory Agents · Nonsteroidal Anti-Inflammatory Drugs
Gyetvai K et al., 1999 · Obstet Gynecol
To examine the effectiveness of any tocolytic compared with a placebo or no tocolytic for preterm labor. We checked MEDLINE (1966-1998) and the Cochrane Controlled Trials Register for articles, using the search terms "randomized controlled trial" (RCT), "preterm labor," "tocolysis," "betamimetics," "ritodrine," "terbutaline," "hexaprenaline," "isoxuprine," "prostaglandin synthetase inhibitors," "indomethacin," "sulindac," "calcium channel blockers," "nifedipine," "oxytocin receptor blockers," "atosiban," "nitroglceride," and "magnesium sulfate." We included all RCTs that compared effect of a tocolytic with a placebo or no tocolytic in women in preterm labor, and reported perinatal, neonatal, or maternal outcomes. Studies were excluded if loss to follow-up exceeded 20% of those originally enrolled, or if data were not reported on a per-patient-treated basis. Eighteen of 76 articles retrieved met the inclusion criteria. TABULATION, INTEGRATION, Two authors independently reviewed the articles and abstracted the data. Discrepancies were resolved by consensus. Meta-analyses (odds ratio [OR] and 95% confidence interval [CI]) were done for each outcome for all trials and for specific types of tocolytic therapy when possible. Tocolytics decreased the risk of delivery within 7 days (OR 0.60, 95% CI 0.38, 0.95). Betamimetics, indomethacin, atosiban, and ethanol, but not magnesium sulfate, were associated with significant prolongations in pregnancy. Tocolytics were not associated with improved perinatal outcomes. Maternal side effects significantly associated with tocolytic use were palpitations, nausea, tremor, chorioamnionitis, hyperglycemia, hypokalemia, and need to discontinue treatment. Although tocolytics prolong pregnancy, they have not been shown to improve perinatal or neonatal outcomes and have adverse effects on women in preterm labor.
Hormonal Agents · Progesterone and Progestins
Travis BE et al., 1993 · Pharmacotherapy
Preterm labor is defined as the onset of uterine contractions in a woman who has completed less than 37 weeks of pregnancy. It may be due to maternal, placental, fetal, or idiopathic causes, and it is associated with a number of risk factors. Nondrug measures such as bedrest and hydration have been used alone or in combination with drug therapy to treat the disorder. Pharmacologic (tocolytic) agents include ethanol, progesterone, indomethacin, nifedipine, beta-adrenergic agonists, and magnesium salts. The three most commonly used drugs are ritodrine, terbutaline, and magnesium.
Prescribing Safety · Medication Safety in Pregnancy
Kosasa TS et al., 1994 · Obstet Gynecol
To determine whether long-term intravenous (IV) tocolysis using combined terbutaline and magnesium sulfate is safe and effective. One thousand consecutive women in preterm labor were treated with combination IV tocolytic therapy. Terbutaline was initiated with an infusion rate of 1.75 micrograms/minute and increased to a maximum of 80 micrograms/minute. Magnesium sulfate was infused at 2 g/hour without any bolus and increased to maintain a serum level of 6.5-7.5 mg/dL. Tocolysis was continued until fetal lung maturity was achieved or delivery occurred. Combination tocolytic therapy prolonged pregnancy by a mean (+/- standard deviation) of 61 +/- 23.6 days in 751 women with intact membranes and by 20.5 +/- 17.4 days in 249 with ruptured membranes. The longest durations of continuous IV tocolysis were 123 days in a patient with intact membranes and 77 days in one with ruptured membranes. The most common side effects were nausea and vomiting, followed by chest tightness and shortness of breath. Long-term IV tocolysis appeared to be safe and to have acceptable side effects, allowing patients to receive combined terbutaline and magnesium sulfate until delivery.
Prescribing Safety · Medication Safety in Pregnancy
Chau AC et al., 1992 · Obstet Gynecol
To compare the tocolytic efficacy and side effects of parenteral and oral magnesium and terbutaline. Ninety-eight patients in labor between 23-35 weeks were prospectively entered into a controlled trial of intravenous and oral magnesium versus subcutaneous and oral terbutaline. Tocolytic effectiveness was judged by delay of delivery for 48 hours or 1 week, and to 37 weeks or more. The need to change therapy to the alternate drug was identified, as were side effects. Entrance characteristics of the population, initial pelvic examination, and concomitant infection or cervicovaginal isolates were noted. Outcomes included gestational age at delivery, birth weights, and Apgar scores. Outcome analysis was based on initial tocolytic therapy. Significantly more patients in the magnesium group delivered at 37 weeks or more: 34 of 46 versus 27 of 52 (P < .05). No significant differences were found for delivery by 48 hours or 1 week. The interval between treatment and delivery was greater for magnesium: 7.1 +/- 3.9 versus 5.0 +/- 3.2 weeks (P < .005). Failure to achieve 37 completed weeks was more often due to obstetric complications than to preterm labor itself. Tocolytic effectiveness was reduced if secondary therapy or re-treatment was required or if the patient had cervical dilatation of 3 cm or greater. Infectious complications were common but were not associated with tocolytic effectiveness. Side effects were more noticeable with oral magnesium and subcutaneous terbutaline. For short-term tocolysis, no significant difference was found between magnesium and terbutaline. Magnesium was associated with a higher term delivery rate. Idiopathic preterm labor accounted for only a small part of the overall prematurity in the study population.