Drug disposition in neonates with patent ductus arteriosus.
OBJECTIVE
To review the literature on the physiologic changes created by neonatal patent ductus arteriosus (PDA) and the potential impact on drug disposition in these infants.


METHODS
An Index Medicus and bibliographic search of the English-language literature pertaining to neonatal PDA and drug usage in newborns.


RESULTS
PDA in premature infants is associated with a variety of physiologic changes that could alter drug disposition. Perfusion of drug-elimination organs (i.e., liver and kidney) may be diminished, resulting in decreased drug elimination. Further, the general fluid overload state associated with PDA may result in larger volumes of distribution (Vd), and dilutional effects for many drugs. Drug absorption, Vd, tissue penetration, and clearance may be affected by the physiologic changes incurred by a PDA. Although the pharmacokinetics of several categories of therapeutic agents may be affected by a PDA, disposition changes with the aminoglycosides and indomethacin have been the best documented. The most reliable pharmacokinetic change appears to be related to drug Vd. The interpretation of many of these studies is confounded by a potential drug interaction with the concurrent administration of indomethacin for PDA closure.


CONCLUSIONS
Close therapeutic drug monitoring is indicated in newborns with PDAs as abrupt changes in drug disposition can occur with PDA closure. PDA-induced changes in specific pharmacokinetic parameters of agents such as the aminoglycosides, indomethacin, and perhaps vancomycin may prove to be a valuable diagnostic adjunct for the identification of babies with undiagnosed PDA. More research into this pharmacophysiologic aspect of pharmacokinetics is warranted.
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Greensboro Area Health Education Center (AHEC), NC 27401.
Gilman
J T
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D000042:Absorption; D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics; D004077:Digoxin / Q000493:pharmacokinetics; D004374:Ductus Arteriosus, Patent / Q000378:metabolism*; D006801:Humans; D007213:Indomethacin / Q000493:pharmacokinetics*; D007231:Infant, Newborn; D007235:Infant, Premature, Diseases / Q000378:metabolism*; D010599:Pharmacokinetics
D000900:Anti-Bacterial Agents; D004077:Digoxin; D007213:Indomethacin