title: Pharmacokinetics of doxapram in idiopathic apnea of prematurity.
abstract: Pharmacokinetics of doxapram were determined in 13 infants with idiopathic apnea of prematurity uncontrolled by aminophylline and caffeine. Doxapram was maintained for 72-96 h at a constant infusion rate of 2-2.5 mg/kg/h. Plasma doxapram levels were measured by gas liquid chromatography. The infants studied had a birth weight of 1,247 +/- 240 g (mean +/- SD), a gestational age of 29.4 +/- 2 weeks and were 9.9 +/- 6 days old. Steady-state plasma doxapram levels reached by all infants averaged 5.8 +/- 1.8 mg/l. Half-life was 6.6 +/- 5.7 h, plasma clearance 0.44 +/- 0.1 litres/kg/h, and calculated volume of distribution 4 +/- 2.7 litres/kg. Doxapram controlled apnea successfully in 12 of 13 babies. A significant fall in PaCO2 and reduction in the rate of apnea was seen within 6-8 h with corresponding doxapram levels of 3.7 +/- 1.8 mg/l. The factors influencing the pharmacokinetics of doxapram in newborns are presently unknown.
authors: Department of Laboratory Medicine, University of Alberta Hospitals, Edmonton, Canada.
authors: M A
authors: MA
authors: Beaudry
authors: J M
authors: JM
authors: Bradley
authors: L M
authors: LM
authors: Gramlich
authors: D
authors: D
authors: LeGatt
mesh_terms: D001049:Apnea / Q000188:drug therapy* / Q000209:etiology / Q000378:metabolism*; D004315:Doxapram / Q000097:blood / Q000493:pharmacokinetics* / Q000494:pharmacology; D005260:Female; D006207:Half-Life; D006801:Humans; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000188:drug therapy / Q000378:metabolism*
chemical_list: D004315:Doxapram