Prematurely born neonates require, amongst others, pharmaceutical therapy. Dosing guidelines for these therapies are often based on data from term born neonates or older infants, while these are... Show morePrematurely born neonates require, amongst others, pharmaceutical therapy. Dosing guidelines for these therapies are often based on data from term born neonates or older infants, while these are not necessarily similar to prematurely born neonates. When suboptimal dosing guidelines are applied the neonates are at risk for under- or overdosing. In this thesis the pharmacokinetics and pharmacodynamics of a variety of drugs frequently used in preterm neonates were characterized, ultimately to optimize treatment. Specifically, caffeine, ibuprofen and fluconazole were studied which are drugs to treat apnea of prematurity, to close a patent ductus arteriosus and to treat or prevent infections with Candida in newborns, respectively. These drugs were introduced and used in clinical practice without sufficient knowledge, especially on appropriate dosing for this subpopulation. For caffeine and ibuprofen we found that the clearance rapidly increases with postnatal age, while for fluconazole clearance is better reflected by body weight and serum creatinine. For these drugs dosing guidelines were proposed based on identified covariates for their pharmacokinetics. Ibuprofen therapy was further investigated by examining the course of spontaneous closure of the ductus arteriosus, and evaluating the effects of ibuprofen exposure and patient characteristics simultaneously. Show less
Although ketamine can be considered to be an “old” drug, a definitive model explainingketamine pharmacokinetics for a wide range of patient populations, dosing regimens and ketamine administrations... Show moreAlthough ketamine can be considered to be an “old” drug, a definitive model explainingketamine pharmacokinetics for a wide range of patient populations, dosing regimens and ketamine administrations forms is lacking. Currently, a large number of ketamine population pharmacokinetic models is published. However, the large number of ketamine pharmacokinetic models based on data from all types of study populations,ketamine dosing regimens and administration forms, can prove to become a serious challenge for clinical decision makers, since it may not always be easy to pick the model that best suits their patient population. In this thesis, we focus on unraveling the complex pharmacokinetics and pharmacodynamics that characterize ketamine, in order to get a step closer to a final “all encompassing” pharmacokinetic-pharmacodynamic model. For the pharmacodynamic outcomes, we especially focus on the effects of ketamine on neuropathic pain, nociceptive pain (pressure pain) and psychedelic outcomes. Show less