Anesthesia & Analgesia, Vol 82, 607-611, Copyright © 1996 by International Anesthesia Research Society
Metoclopramide exaggerates stress-induced tachycardia in pregnant sheep
JC Eisenach and DM Dewan
Department of Anesthesia, Wake Forest University Medical Center, Winston-Salem, NC 27157-1009, USA.
Metoclopramide is often administered to hasten gastric emptying prior to
cesarean section and during labor, but has also been demonstrated to
increase catecholamine release during stress and to increase heart rate and
blood pressure in nonpregnant humans. The purpose of this study was to
examine the maternal and fetal effects of metoclopramide during maternal
stress in pregnant ewes. After baseline measures, eight ewes were randomly
allocated to receive either intravenous metoclopramide, 10 mg, or saline,
followed in 10 min by nonpainful stress to increase mean arterial pressure
40%-45% for 30 s. At least 2 days later, the ewes received the alternate
treatment. Metoclopramide, but not saline, increased resting maternal heart
rate. In the 10 min after maternal stress, maternal heart rate was
increased more after metoclopramide than after saline treatment, whereas
maternal blood pressure, uterine blood flow, and fetal hemodynamic
variables and arterial blood gas tensions did not differ between the two
treatments. Whereas these results are not consistent with a generalized
increase in sympathetic nervous system tone after a single dose of
metoclopramide, they do suggest that metoclopramide may exaggerate
tachycardia after stress, encountered frequently both during and after
cesarean section.