Newborn infants are not small adults. The pharmacokinetics and dynamics of analgesic drugs are immature at birth. Volumes of distribution, drug clearances, side-effects and drug efficacy all differ in newborns as compared to adults. Interestingly, these parameters develop before birth and during the postnatal period, reaching adult values after a period of months or years. This means that clinicians should anticipate on pharmacokinetic/pharmacodynamic (PK/PD) changes in newborns with increasing postconceptual age. The ability to perceive pain might also be immature at birth. Lower pain thresholds due to the absence of inhibitory descending spinothalamic fibers and a not yet fully developed cortical pain memory system are points of interest for our understanding of differences in pain perception in the newborn infant. Although this is a relatively unexplored area of research in humans, we will discuss the maturation and development of neonatal pain experience and perception in this paper.

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Seminars in Fetal & Neonatal Medicine
Department of Pediatric Surgery

Simons, S.H.P, & Tibboel, D. (2006). Pain perception development and maturation. Seminars in Fetal & Neonatal Medicine, 11(4), 227–231. doi:10.1016/j.siny.2006.02.010