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Pregnancy enhances cocaine's actions on the heart and within the peripheral circulation
J R Woods1, K J Scott, M A Plessinger
1Division of Maternal-Fetal Medicine, University of Rochester School of Medicine and Dentistry, NY.
Objective:
Our purpose was to determine whether cocaine's enhanced cardiovascular actions in pregnancy are cardiac alone or involve the peripheral vascular system.
Study Design:
Six pregnant and five nonpregnant ewes chronically instrumented for heart rate, blood pressure, cardiac output, and systemic vascular resistance were given cocaine at 1.0 and 2.0 mg/kg and monitored for 60 minutes. Blood samples for cocaine levels were taken at 5, 15, 30, and 60 minutes.
Results:
Cocaine initially (first 60 seconds) produced increased heart rate, decreased cardiac output, decreased stroke volume, and increased cardiac oxygen consumption, which were greater in pregnant than nonpregnant ewes. After 1 minute recovery of cardiac responses was accompanied by increased systemic vascular resistance, which was greater at each dose in pregnant than nonpregnant ewes. Cocaine levels at 5 minutes for pregnant ewes were eightfold to tenfold higher than for nonpregnant ewes.
Conclusion:
Cocaine produces cardiovascular alterations that are dose and time related but, in each case, enhanced in pregnant ewes. Cocaine metabolism may contribute to this pregnancy-related phenomenon.