Clinical pharmacology of non opioid analgesics in neonates

An integrated approach of neonatal analgesia starts with the systematic evaluation of pain and should be followed by effective interventions, mainly based on the appropriate (i.e. safe and effective) administration of analgesics. In contrast to the more potent opioids, data on the pharmacokinetics and -dynamics of non-opioid analgesics in this specific population are still rare or even lacking. We therefore evaluated various aspects of developmental pharmacology of non-opioid analgesics (paracetamol, ibuprofen, acetylsalicyl acid) in neonates. We first performed a single dose propacetamol study in preterm and term neonates. Based on these preliminary findings, a repeated dose administration scheme was developed and tested and maturational aspects from preterm till teenage were documented. Although non-selective COX-inhibitors might be effective in the treatment of postoperative or inflammatory pain syndromes in neonates, potential efficacy should be balanced against the drugs' safety profile. Neonatal renal clearance strongly depends on glomerular filtration rate (GFR) and GFR itself strongly depends on the vaso-dilatative of prostaglandins on the afferent arterioli. We therefore evaluated the impact of the administration of ibuprofen or acetylsalicylic acid on renal clearance in preterm infants and hereby used amikacin clearance as a surrogate marker. We hereby documented the negative effect of ibuprofen on glomerular filtration rate in preterm infants up to 34 weeks and we were able to show that ibuprofen and acetylsalicylic acid had an equal impact on the glomerular filtration rate.