Abstract No: 9
METABOLIC AND HAEMODYNAMIC EFFECTS AFTER NIFEDIPINE AND
RITODRINE TOCOLYSIS
1D.N.M.
Papatsonis, 2H.P. van Geijn, 3O.P. Bleker, 4H.A. Adèr,
5
G.A. Dekker
1,2
Division of Maternal-Fetal medicine, Depat. of OB/Gyn, Free University Hospital
Amsterdam, 3Depat. of OB/Gyn, Academic Medical Center University of Amsterdam,
4
Depat. of Clinical Epidemiology and Biostatistics, Free University Hospital Amsterdam,
The Netherlands, 5Depat. of Obstetrics and Gynecology, Adelaide University, Australia
Abstract Introduction The most commonly used tocolytic agents are the betamimetics.
Calcium channel blockers are more frequently used because they have shown a better
tocolytic efficacy, lower incidence of side effects and a better perinatal outcome compared
with betamimetics. The aim of this study is to compare the haemodynamic and metabolic
changes after ritodrine and nifedipine tocolysis. Material and Methods An open
randomized trial were patients with preterm labor were allocated to ritodrine intravenously
or nifedipine orally. Blood pressure and maternal heart rate were measured before starting
tocolysis, and after 24 and 48 hours of tocolysis. Fasting serum glucose levels, and serum
potassium levels were measured before starting tocolysis, after 48 hours, and after 5 days
of tocolysis.
Results Mean diastolic blood pressure was significantly lower in the
ritodrine group after 24 hours of tocolysis (65 ± 12 vs. 70 ± 8, P= 0.001), and after 48
hours of tocolysis (65 ± 12 vs. 71 ± 8, P=0.004) compared with the nifedipine group. Mean
maternal heart rate was significantly higher in the ritodrine group after 24 hours (105 ± 17
vs. 86 ± 13, P < 0.0001), and 48 hours (100 ± 21 vs. 85 ± 12, P< 0.0001) of tocolysis
compared with the nifedipine group. Mean fasting glucose levels were significantly higher
in the ritodrine group after 48 hours of tocolysis compared with the nifedipine group (6.68
± 2.53 vs. 4.93 ± 1.23, P=0.0016). Mean potassium levels were significantly lower in the
ritodrine group after 48 hours of tocolysis compared with the nifedipine group (3.52 ± 0.84
vs. 3.81 ± 0.45, P=0.04). Conclusions Use of nifedipine for preterm labor is associated
with a lower incidence of adverse heamodynamic alterations compared with ritodrine after
24 and 48 hours of tocolysis. Mean blood glucose levels are significantly higher in the
ritodrine group after 48 hours of tocolysis compared with nifedipine. Mean potassium
levels are significantly lower in the ritodrine group after 48 hours of tocolysis compared
with nifedipine. Use of nifedipine is associated with less adverse heamodynamic and
metabolic changes compared with ritodrine. In our opinion nifedipine is the preferred drug
of choice for the treatment of preterm labor.