Open AccessThe Influence of Dose‐Delivery time Interval on Neonatal Plasma Pethidine Levels
Author(s) -
Moreland Terence A.,
Brice John E. H.,
Mohamdee Omar,
Walker Colin H. M.
Publication year - 1983
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.3109/00016348309156247
Subject(s) - medicine , pethidine , anesthesia , plasma levels , interval (graph theory) , endocrinology , analgesic , mathematics , combinatorics
. Plasma pethidine levels were determined by RIA during the first 24h of life in 126 neonates whose mothers had received a single intramuscular dose of 100‐150 mg pethidine HC1 0.25 to 19.5 h before delivery. The mean (geometric) maternal and cord venous plasma pethidine concentration and the neonatal capillary plasma levels at 0.5, 1.5 and 12‐24 h expressed per unit dose were 125, 98, 71, 59 and 23 ng/ml per mg/kg respectively. The mean (±S.E.M.) cord: maternal plasma concentration ratio was 0.741±0.036 (n = 40). The ratio was significantly correlated with the dose‐delivery interval, r = 0.42, p>0.01. The pethidine concentration in cord and in neonatal capillary plasma was significantly correlated to the weight related dose, r = 0.25 to 0.48, p=0.01. Cord venous levels of pethidine rose rapidly after drug administration but neonatal capillary levels increased slowly to reach peak levels at 2 to 5 h before declining over the next 15 to 18 h. The maternal plasma pethidine half‐life, 5.59 h was considerably shorter than that observed in the newborn, 15.94 h.