Percutaneous lignocaine absorption in newborn infants.

The permeability of the skin of newborn infants to lignocaine was examined in vitro using excised skin. Samples were studied from 24 infants of gestational age 25 to 40 weeks and postnatal age 0 to 7 days. Mature skin was relatively impermeable to lignocaine, but the more premature infants showed a marked increase in absorption. There was a strong inverse correlation between gestational age and skin permeability. These findings suggest that topical lignocaine would be an effective local anaesthetic in preterm infants. Calculations indicate that there is negligible risk of toxicity due to systemic absorption.