[Post-dosage loading concentrations of theophylline and pharmacokinetic study after the fifth maintenance dosage in premature newborns with apnea].
From a group of 50 premature newborns with central and mixed apnea, 34 received a loading dose of 4.3 mg/kg intravenous theophylline (group I) and 16 received 6 mg/kg orally (group II); the maintenance dose was 0.86 and 1 mg/kg every eight hours, respectively. Mean maximum serum concentrations after the loading dose were 5.8 +/- 2.3 mcg/mL in 25 newborns from group I, and 6.6 +/- 1,3 mcg/mL in 8 newborns from group II (P less than 0.20). Mean maximum concentration after the fifth maintenance dose was 7.5 +/- 1.7 mcg/mL in 26 newborns from group I, and 5.8 +/- 1.4 mcg/mL in 16 newborns from group II (P = 0.001); mean minimum concentration was 5.3 +/- 1.6 mcg/mL and 4.5 +/- 1.4 mcg/mL, respectively (P greater than 0.10). Mean clearance was 30.21 +/- 11.03 and 27.1 +/- 7.7 mL/kg/h; mean apparent distribution volume was 0.5 +/- 0.25 and 0.76 +/- 0.32 L/kg; elimination rate constant was 0.049 +/- 0.04 and 0.040 +/- 0.03/h-1 for both groups respectively, with significant differences between groups only in the apparent distribution volume (P less than 0.001). Half-life time (T1/2) was from four to 118 hours. The study population was divided into three groups according to half-life time: those with a half-life time of lesser than 20 hours (47.6%); an intermediate half-life time of from 20 to 30 hours (23.8%); and a long half-life time of more than 31 hours (28.6%).(ABSTRACT TRUNCATED AT 250 WORDS)
Rodríguez-Palomares
C
C
Departamento de Farmacología Clínica, Instituto Nacional de Perinatología, México, D.F.
Udaeta-Mora
E
E
González-Treviño
J
J
Juárez-Olguín
H
H
Calderón-Mandujano
B
B
Prado-Serrano
A
A
Belmont-Gómez
A
A
D000284:Administration, Oral; D001049:Apnea / Q000097:blood / Q000188:drug therapy*; D004334:Drug Administration Schedule; D006207:Half-Life; D006801:Humans; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000097:blood / Q000188:drug therapy*; D007275:Injections, Intravenous; D013806:Theophylline / Q000008:administration & dosage / Q000493:pharmacokinetics*
D013806:Theophylline
Concentraciones de teofilina postdosis de impregnación y estudio farmacocinético en la quinta dosis de mantenimiento en recién nacidos pretérmino con apneas.