History and Objectives: Due to the high mortality rate and the high incidence of complications of severe preeclampsia throughout the world particularly in the developing countries and regarding the controversies on the therapeutic effects and complications of Nifedipine and Hydralazine and in order to compare the therapeutic effect of this 2 medications, the present study was performed on patients with severe preeclampsia hospitalized at Shabihkhani maternity hospital during the years 1367 and 1377.

Materials and Methods: A clinical trial study was performed on patients with ?+2 proteinuria, blood pressure of 160/110 that was measured at least on 2 occasions at an interval of 3 hours or clinical manifestations of severe preeclampsia. Patients were randomly classified into 2 groups. In one group sublingual Nifedipine was administered at a dose of 5 milligrams (Equal to 5 drops) and in the other group, which was considered as the control group, Hydralazine was administered as injection at a dose of 5 milligrams. The effect of the medication on systolic and diastolic blood pressure, fetal heat rate and urinary volume was evaluated at 30 and 60 minutes after the administration of the medication. Also the effect of the medication on Apgar score and hospital length of stay of the neonates were studied.

Results: 2 group were similar, percent reduction of systolic blood pressure 30 minutes after the administration of the medication was 11.4% and 8.03% in the Nifedipine and Hydralazine group respectively (P<0.01) and the percent reduction of diastolic blood pressure 30 minutes after the administration of the medication was 18.7% and 10.9% in the Nifedipine and Hydralazine group respectively (P<0.01). Average urine volume 30 and 60 minutes after the administration of the medication were 68 and 128.8 milliliters in the Nifedipine group and 29.3 and 53.8 milliliters in the Hydralazine group (P<0.01). Average fetal heat rate changes thirty and 60 minutes after the administration of the medication were 1.36 and 0.92 in the Nifedipine group and -2.4 and -1.77 in the Hydralazine group.

Conclusion: Nifedipine administration results in a more fall in systolic and diastolic blood pressure and a more urine volume production than Hydralazine. Hydralazine produces a significant decrease in fetal heart rate. Apgar score at five minutes and hospital length of stay of the neonates does not differ significantly in the Nifedipine group in comparison with the Hydralazine one.