Nifedipine Increases Urinary Excretion of Prostacyclin Metabolite in Hypertensive Pregnancy

: Renal prostanoid excretion was investigated in nine hypertensive pregnant patients before and during treatment with nifedipine 10 mg orally t.i.d. Urinary excretion of prostacyclin (measured as 6-ketoprostaglandin Fla, 6-keto-PGF1a) increased by 77% during nifedipine treatment (P<0.05). No changes were found in prostaglandin E2 (PGE2) and thromboxane A2 (as thromboxane B2, TXB2 excretions. A significant reduction in blood pressure did not correlate with an increase in 6-keto-PGFla excretion. Plasma prekallikrein and urinary kallikrein and catecholamine excretions remained unaltered. In six normotensive non-pregnant women, increase in 6-keto-PGFla excretion during nifedipine treatment was not significant. No changes in PGE2 and TXB2 excretions were found, whereas plasma prekallikrein was reduced (P < 0.05) and urinary excretion of kallikrein (P<0.05) and noradrenaline (P = 0.06) increased under nifedipine. The results suggest that nifedipine enhances the renal 6-keto-PGF10 excretion in hypertensive pregnancy.