Oral indometacin abolished hypotensive effects of intravenous hydralazine in one study, but no effect was found in another.In patients with pulmonary hypertension, intravenous indometacin reduced effects of intravenous hydralazine, and in patients with hypertension, intravenous diclofenac reduced theeffects of intravenous dihydralazine.
Clinical evidence,mechanism, importance and management
In 9 healthy subjects, oral indometacin 50mg every 6 hrs for 4 doses abolished hypotensive response to intravenous hydralazine 150 micrograms/kg, and subjects only responded when given another dose of hydralazine 30 minutes later (See reference number 1). A study in 7 patients with pulmonary hypertension given indometacin 50mg and hydralazine 350 micrograms/kg, both intravenously, either alone, or concurrently, also found that effects of hydralazine (reduction in systemic arterial pressure, heart rate, cardiac index) were reduced by indometacin (See reference number 2). In contrast,another study in 9 healthy subjects(See reference number 3) found that oral indometacin 25mg four times daily for 2.5 days did not affect hypotensive response to a single 200-microgram/kg intravenous dose of hydralazine.
Thus it is not clear if indometacin interacts with intravenous hydralazine,and it is uncertain if an interaction occurs when hydralazine is given orally.
On other hand, a single-dose study in 4 hypertensive subjects found that actions of intravenous dihydralazine (effects on blood pressure, urinary excretion, heart rate and sodium clearance) were reduced by intra
NSAIDs can cause increases in blood pressure due to their effects on sodium and water retention. Various NSAIDs have been reported to reduce efficacy of other antihypertensive drug classes, for example see ACE inhibitors + NSAIDs interaction. It would therefore be prudent to monitor concurrent use of hydralazine and NSAIDs.
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Jackson SHD,Pickles H. Indomethacin does not attenuate the effects of hydralazine in normalsubjects. Eur J Clin Pharmacol (1983) 25, 303–5.
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