Children differ from adults with respect to growth and development but also immaturity of various pharmacological mechanisms. Dosing schemes in children are usually derived in an empirical manner from clinical trials in adult patient groups. All this poses neonates to an increased risk for therapeutic failure and adverse drug reactions.

Medicinal products studied during this project are among the ones with the highest needs for research in the pediatric intensive care. This project focuses on the necessity to integrate subject's individual characteristics to assist clinical decision-making in drug therapy. The investigators explore the mechanisms defining the dose response in pediatric populations. The results obtained with these studies will help to find safer drug dosing regimens in this delicate patient population.

Inclusion Criteria:

• Given informed consent by the guardian of an eligible patient.
• Patient is more than 24 weeks old and has a body weight more than 500 g.
• Patient needs intensive care treatment based on a clinical decision by a neonatologist and receives propofol or oxycodone on their therapy. Attending neonatologist makes the decision to prescribe propofol for scheduled short procedural sedation or oxycodone for analgesia as well as all other treatment related decisions.

Exclusion Criteria:

• Eligible patients guardian declines to give informed consent.
• A previous history of intolerance to the study drugs or to related compounds and additives.
• History of any kind of drug allergy.
• Participation in any other studies concomitantly or within one month prior to the entry into this study.