Cimetidine as pre-anesthetic agent for cesarean section: perinatal effects on the infant, the placental transfer of cimetidine and its elimination in the infants.

In a prospective randomized study of 39 consecutive cesarean sections, 20 patients received cimetidine 400 mg intramuscularly as a pre-anesthetic, an 19 control patients were given NaCl. No perinatal effects on the infants were observed by cardiotocography before delivery, and K, Na, pH, PCO2, HCO-3 and glucose values in capillary blood were nearly identical in the two groups 2 hours after birth, the difference being non-significant (p greater than 0.05). No respiratory effects or arrhythmias were observed. In another study comprising 8 elective cesarean sections in patients with uncomplicated pregnancies, cimetidine was found to cross the placenta at a maternal/cord blood ratio of 3:1. The drug could not be detected in any of the infants 2 hours after delivery.