Pulsatile vs. continuous parenteral tocolysis: comparison of side effects

Bolus tocolysis has been developed to reduce the dose of fenoterol compared to continuous tocolysis. Whereas the high efficacy of pulsatile applicatio n of fenoterol has been shown, the proof of reduced side effects is still l acking. A total of 59 patients with preterm labor were divided in three gro ups: (1) continuous tocolysis and oral application of magnesium (n=19), (2) continuous tocolysis and parenteral application of magnesium (n=20), (3) p ulsatile tocolysis (bolus tocolysis) and oral application of magnesium (n=2 0). Heart rate, systolic and diastolic blood pressure, serum K+ and serum M g++ were quantified before tocolysis and after 2, 8 and 24 h. P-blockers an d water balance were recorded over 24 h. Subjective side effects were quant ified using a questionnaire with scales graduated covering palpitations, tr emor, diaphoresis, thirst, precardialgia and nausea/vomiting. The analysis of the data revealed significantly fewer side effects concerning heart rate , plasma K+ level and the subjective side effects among patients treated wi th bolus tocolysis than among those treated with continuous tocolysis. Betw een the latter two groups, no significant difference was found. Concerning blood pressure and need for P-blockers, no significant differences were fou nd between the three groups. The results of the present study show that esp ecially the side effects subjectively found to be disagreeable by the patie nts are reduced by pulsatile tocolysis, whereas other side effects show onl y slight differences between the study groups. (C) 1999 Elsevier Science Ir eland Ltd. All rights reserved.