Pharmacodynamics and pharmacokinetics of cyclosporin A in the newborn pig.

The disposition kinetics of cyclosporin A in the neonates as well as age-related differences in lymphocyte responses to cyclosporin A are unknown. A single intravenous infusion of cyclosporin A was given to neonatal (2.5 or 5 mg/kg) and mature pigs (10 mg/kg) and blood cyclosporin A levels were measured by RIA. The neonates had longer elimination half-life and lower drug clearance than mature animals. Suppression in lymphocyte proliferation was only observed in mixed lymphocyte reaction and phytohemagglutinin-stimulated cultures of the 2-hour samples from neonates receiving 5 mg/kg. We conclude that neonatal pig exhibit different cyclosporin A pharmacokinetics and show higher sensitivity to cyclosporin A than mature animals.