INFLUENCE OF NONSTEROIDAL ANTIINFLAMMATORY DRUGS ON RENAL-FUNCTION AND 24H AMBULATORY BLOOD PRESSURE-REDUCING EFFECTS OF ENALAPRIL AND NIFEDIPINE GASTROINTESTINAL THERAPEUTIC SYSTEM IN HYPERTENSIVE PATIENTS

Objective: To evaluate the influence of non-steroidal anti-inflammator y drugs (NSAIDs; aspirin and indomethacin) on the renal and antihypert ensive effects of enalapril and nifedipine gastrointestinal therapeuti c system (GITS) in patients with essential hypertension. Design and me thods: In a crossover study, 18 patients on an unrestricted-salt diet were randomly assigned to receive either enalapril (20-40 mg/day) or n ifedipine-GITS (30-60 mg/day) for 4-8 weeks, followed by aspirin (100 mg/day for 2 weeks) and then indomethacin (75 mg/day for 1 week). Bloo d pressure was measured by 24 h ambulatory monitoring. Results: Enalap ril and nifedipine-CITS significantly reduced blood pressure compared with placebo. Aspirin did not alter the antihypertensive effect of eit her drug. Indomethacin attenuated (by 45%) the antihypertensive effect of enalapril throughout the 24 h period of evaluation, but did not in terfere with the effect of nifedipine. Furthermore, indomethacin signi ficantly reduced the fractional excretion of sodium and plasma levels of prostaglandins in a similar way when added to either the enalapril or the nifedipine regimen. Conclusions: Vasodilatory prostaglandins ar e probably involved in the antihypertensive effects of enalapril but n ot of nifedipine, and this interaction seems to be independent of any indomethacin-induced decrease in renal sodium excretion. Nifedipine ma y be an appropriate drug to treat hypertensive patients requiring conc omitant therapy with NSAID.