Randomised comparison between a loading and incremental dose model for ritodrine administration in preterm labour.
OBJECTIVE
To compare a new loading dose regimen for intravenous ritodrine administration in preterm labour with the conventional dose regimen.


METHODS
Multicentre randomised trial using numbered opaque sealed envelopes.


METHODS
Five teaching hospitals in the Netherlands.


METHODS
Women (n = 203) in preterm labour at less than 34 weeks of gestation.


METHODS
Women received either a loading dose ritodrine infusion followed, as soon as tocolysis was reached, by a decrease in infusion rate or the conventional schedule of increasing doses until uterine quiescence was achieved.


RESULTS
Frequency of successful tocolysis (71%) and duration of treatment (55 h) were similar in both groups, but the loading dose schedule was better tolerated with fewer adverse events. Also the number of dose adjustments was smaller than in the incremental dose group (P < 0.001). Overall, the differences between the two regimens were unexpectedly small.


CONCLUSIONS
Despite the small differences, the loading model is easier to apply, requires fewer dose adjustments, is better tolerated with less side effects, and reduces the likelihood of clinical error.
Holleboom
C A
CA
Department of Obstetrics and Gynaecology, Bronovo Hospital, The Hague, The Netherlands.
Merkus
J M
JM
van Elferen
L W
LW
Keirse
M J
MJ
D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006340:Heart Rate, Fetal / Q000187:drug effects; D006801:Humans; D007260:Infusion Pumps; D007262:Infusions, Intravenous; D007752:Obstetric Labor, Premature / Q000517:prevention & control*; D011247:Pregnancy; D012312:Ritodrine / Q000008:administration & dosage*; D015149:Tocolytic Agents / Q000008:administration & dosage*; D016896:Treatment Outcome
D015149:Tocolytic Agents; D012312:Ritodrine