PREGNANCY ENHANCES COCAINE ACTIONS ON THE HEART AND WITHIN THE PERIPHERAL-CIRCULATION

OBJECTIVE: Our purpose was to determine whether cocaine's enhanced car diovascular actions in pregnancy are cardiac alone or involve the peri pheral vascular system. STUDY DESIGN: Six pregnant and five nonpregnan t ewes chronically instrumented for heart rate, blood pressure, cardia c output, and systemic vascular resistance were given cocaine at 1.0 a nd 2.0 mg/kg and monitored for 60 minutes. Blood samples for cocaine l evels were taken at 5, 15, 30, and 60 minutes. RESULTS: Cocaine initia lly (first 60 seconds) produced increased heart rate, decreased cardia c output, decreased stroke volume, and increased cardiac oxygen consum ption, which were greater in pregnant than nonpregnant ewes. After 1 m inute recovery of cardiac responses was accompanied by increased syste mic vascular resistance, which was greater at each dose in pregnant th an nonpregnant ewes. Cocaine levels at 5 minutes for pregnant ewes wer e eightfold to tenfold higher than for nonpregnant ewes. CONCLUSION: C ocaine produces cardiovascular alterations that are dose and time rela ted but, in each case, enhanced in pregnant ewes. Cocaine metabolism m ay contribute to this pregnancy-related phenomenon.