Table 5.
Pharmacokinetic parameters of nifedipine as tocolytic
| Study | Ferguson et al. [63] | Marin et al. [67] | Papatsonis et al. [58] | Silberschmidt et al. [59] | Haas et al. [60] | Haas et al. [64] | Ter Laak et al. [56] |
|---|---|---|---|---|---|---|---|
| Oral dose | 10–40 mg in first hour followed by 20 mg/4–6 h (sublingual) | * followed by 60 mg continuous release nifedipine | * followed by 20 mg slow release (T = 105 min) | 30–150 mg/day tablets with sustained release | * and 1 × 20 mg (T = 105 min) | 10–20 mg/6–8 h | 20 mg/6 h vs. placebo |
| Elimination half-life (t1/2) | 81 min (49–137) | NA | NA |
maternal 17.4 h (95% CI: 13.9–21.7); fetal (umbilical cord) 20.4 h (95% CI: 15.7–26.3) |
NA | 1.68 ± 1.56 h | 2–5 h |
| Volume of distribution (Vd) | NA | NA | NA | NA | NA | NA | 6.2 ± 1.9 L/kg |
| Time of maximum serum concentration (Tmax) | NA | NA | 1.2 ± 0.1 h | `NA | 1 h | NA | NA |
| Maximum serum concentration | 96.7 ± 45.3 (23.4–197.9) ng/mL | NA | 127 ± 44 | NA | NA | NA | NA |
| Area under the plasma drug concentration–time curve (AUC) | NA | NA | NA | NA | Mean 86.1 ± 61.1 µg*h/L | AUC0-6 h: 207 ± 138 µg*h/L | NA |
| Maternal mean nifedipine concentration | 7.2 ± 5.5 ng/mL after 20 mg nifedipine orally every 6 h | 32.9 ± 25.1 ng/mL (6–101 ng/mL) | 67.4 ± 28.4 ng/mL | NA | NA | NA | 16.8 ng/mL (median concentration at SS) |
| Neonatal serum plasma concentration after delivery | 1.8–29.5 ng/mL (N = 5) | NA | NA | NA | NA | NA | NA |
Given means are reported ± SD unless stated otherwise
NA not applicable, h hours
*4 × 10 mg nifedipine (T = 0, 15, 30, 45 min)