Safety of intra-amniotic and intra-fetal digoxin administration before late second trimester abortion by dilation and evacuation
Awarded 2008
Large Research Grants
Eleanor Drey, MD, EdM
University of California, San Francisco

Objective: The purpose of this study was to determine the safety of two routes and doses of digoxin before later second-trimester abortion by dilation and evacuation through an assessment of maternal systemic digoxin absorption, cardiac rhythm and coagulation parameters. Study Design: Pregnant women at between 19 and 23 weeks’ gestation received either 1.5 mg digoxin through intra-amniotic injection (IAI) or 1.0 mg digoxin through intra-fetal injection (IFI). They then had serum digoxin levels determined for 48 hours and Holter cardiac monitoring performed for 24 hours. Clotting parameters were assessed before digoxin injection and 24 hours later, at the time of the dilation and evacuation. Results: Ten patients in each group completed the study. The mean (+SD) serum digoxin peak concentration in the IAI group was 1.5. +0.72 mcg/L (range 0.7-2.9 mcg/L) and in IFI 1.4 +0.74 mcg/L (range 0.5-2.4 mcg/L). The mean (+SD) time to peak digoxin concentration was in the IAI 10.7 +8.5 hours (range, 1-24 hours) and in the IFI 1.5 +0.97 hours (range, 1-4 hours). Ambulatory cardiac monitoring showed no rhythm or conduction abnormalities associated with digoxin. Prothrombin and partial thromboplastin time levels did not change significantly before the injection and after the dilation and evacuation (12.9 to 13.4 seconds and 28.4 to 28.4 respectively in the IAI; and 13.1 to 13.4 seconds, and 28.6 to 29.2 seconds, respectively in the IFI). Abdominal pain or cramping and fatigue were the most common complaints in both groups after the injection and osmotic dilator placement. Subjects qualitatively had mixed feelings about whether they would want the injection if it were offered to them in the future. Conclusion: Although our findings remain preliminary, the maximum digoxin concentration peak achieved after 1.5 mg IAI and 1 mg IFI generally was in the low therapeutic range, except for two patients in the IAI and three in the IFI groups who had “critical” values. No cardiac rhythm or conduction abnormalities associated with digoxin were noted by Holter monitoring. Coagulation parameters did not change significantly. Given that in our small pharmacokinetic safety study, five patients had “critical” serum digoxin levels of uncertain health signficance, the clinical importance of digoxin injection to cause fetal demise should be carefully considered before employing these injections before late second-trimester dilation and evacuations.

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