Comparison of the efficacy of the immediate-release and osmotic push-pull system formulations of nifedipine for tocolysis.

AIM: To compare the immediate-release (IR) and osmotic push-pull system formulations of nifedipine used for tocolysis in prolonging pregnancy, neonatal outcomes and maternal-fetal adverse effects.

METHODS: We evaluated 140 pregnant women who received the IR (n = 72) and osmotic push-pull system (n = 68) formulations of nifedipine for tocolysis due to threatened preterm labor between 240/7 and 336/7 weeks of gestation. Groups were compared in terms of efficacy of tocolysis in prolonging pregnancy for more than 48 h, 7 days and up to 37 weeks of gestation, total number of days gained for prolonging pregnancy, delivery weeks, maternal-fetal adverse effects and neonatal outcomes including ventilation support, need for intubation or surfactant, intraventricular hemorrhage, respiratory distress syndrome, necrotizing enterocolitis, admission to neonatal intensive care unit, neonatal death, Apgar scores at the 1st and 5th minutes.

RESULTS: There was no significant difference between the two groups in prolonging pregnancy for more than 48 h or 7 days, total number of days gained after tocolysis initiation, delivery weeks, the number of births at 340/7 -366/7 weeks or after 37 weeks of gestation (P > 0.05). Maternal-fetal adverse effects and neonatal outcomes were similar in both groups (P > 0.05).

CONCLUSION: The efficacy of IR and osmotic push-pull system formulations of nifedipine have similar effects in terms of tocolysis and neonatal outcomes, adverse effects. Osmotic push-pull system formulation of nifedipine may be an alternative medication in tocolytic therapy due to its ease of use and the absence of loading dose necessity.