METHODS: Nine healthy normotensive subjects participated in this randomized placebo-controlled two-way crossover study examining the effects of 5 days' pretreatment of nafcillin 500 mg or placebo four times daily on the pharmacokinetics of an oral dose of nifedipine 10 mg. Plasma nifedipine concentrations were measured by gas chromatography-mass spectro.

RESULTS: The area under the plasma nifedipine concentration-time curve (AUC0-alpha) in nafcillin-pretreated subjects (80.9 +/- 32.9 micro g l-1 h-1) was significantly decreased compared with subjects who received only nifedipine (216.4 +/- 93.2 micro g l-1 h-1) (P < 0.001). Total plasma clearance of nifedipine (CL/F) was significantly increased with nafcillin pretreatment (138.5 +/- 42.0 l h-1 vs 56.5 +/- 32.0 l h-1) (P < 0.002).

METHODS: Subjects were 200 consecutive patients admitted to Kuala Tereng-ganu General Hospital, Malaysia with severe hypertension in pregnancy between August 1989 and June 1990. Admission criteria were an ongoing viable pregnancy more than 28 weeks and diastolic blood pressure (DBP) more than 120 mmHg. The patients were randomly divided into 2 groups. In group I, sublingual nifedipine 5 mg was administered and repeated after 15 minutes if DBP > 120 mmHg; and in group II hydrallazine 5 mg was intravenously injected and repeated after 15 minutes if DBP > 120 mmHg. Both groups were put on hydrallazine infusion if DBP > 120 mmHg after 30 minutes. The Chi-square test was used for analysis with significance at p < 0.05.

RESULTS: There was no statistical difference in the efficacy of therapy for decreasing blood pressure between the 2 groups. The groups were comparable by age, parity, gestational age at presentation, birth weight of infants, incidence of postpartum haemorrhage and fetal distress. Caesarian section rates were similar. In the observational studies on nurses administering the drugs, no significant difficulties were observed.

OBJECTIVES: To evaluate the effectiveness of maintenance tocolytic therapy with oral nifedipine on the reduction of adverse neonatal outcomes and the prolongation of pregnancy by performing an individual patient data meta-analysis (IPDMA).

SEARCH STRATEGY: We searched PubMed, Embase, and Cochrane databases for randomised controlled trials of maintenance tocolysis therapy with nifedipine in preterm labour.

SELECTION CRITERIA: We selected trials including pregnant women between 24 and 36(6/7)  weeks of gestation (gestational age, GA) with imminent preterm labour who had not delivered after 48 hours of initial tocolysis, and compared maintenance nifedipine tocolysis with placebo/no treatment.

DATA COLLECTION AND ANALYSIS: The primary outcome was perinatal mortality. Secondary outcome measures were intraventricular haemorrhage (IVH), necrotising enterocolitis (NEC), infant respiratory distress syndrome (IRDS), prolongation of pregnancy, GA at delivery, birthweight, neonatal intensive care unit admission, and number of days on ventilation support. Pre-specified subgroup analyses were performed.

MAIN RESULTS: Six randomised controlled trials were included in this IPDMA, encompassing data from 787 patients (n = 390 for nifedipine; n = 397 for placebo/no treatment). There was no difference between the groups for the incidence of perinatal death (risk ratio, RR 1.36; 95% confidence interval, 95% CI 0.35-5.33), intraventricular haemorrhage (IVH) ≥ grade II (RR 0.65; 95% CI 0.16-2.67), necrotising enterocolitis (NEC) (RR 1.15; 95% CI 0.50-2.65), infant respiratory distress syndrome (IRDS) (RR 0.98; 95% CI 0.51-1.85), and prolongation of pregnancy (hazard ratio, HR 0.74; 95% CI 0.55-1.01).

CONCLUSION: Maintenance tocolysis is not associated with improved perinatal outcome and is therefore not recommended for routine practice.