Nifedipine Indometacin

The interaction between indometacin and ACE inhibitors is well established, with several studies showing that indometacin can reduce the blood pressure-lowering effect ofa number of ACE inhibitors. The interaction may not occur in all patients. If indometacin is required in a patient taking any ACE inhibitor, it would be prudent to monitor blood pressure. In a few small comparative studies, indometacin has been shown to have less effect on the calcium-channel blockers amlodipine, felodipine, and nifedipine, than on enalapril. See also, Calcium-channel blockers -i-Aspirin or NSAIDs , p.861. Therefore, a calcium-channel blocker may sometimes be an alternative to an ACE inhibitor in a patient requiring indometacin. 

There is evidence that most NSAIDs can increase blood pressure in patients treated with antihypertensives, although some studies have not found the increase to be clinically relevant. In various small studies, indometacin appeared not to reduce the hypotensive effects of amlodipine, felodipine, nicardipine, nimodipine or verapamil, but it did in one of two studies with nifedipine, and one study with nitrendipine. Similarly, ibuprofen caused a small reduction in the antihypertensive effects of amlodipine. Diclofenac and sulindac appear not to interact with nifedipine, nor ibuprofen, naproxen, piroxicam or sulindac with verapamil, nor naproxen with nicardipine. Low-dose aspirin did not alter the antihypertensive effect of felodipine or nifedipine in one study, and long-term aspirin did not alter the cardiovascular benefits of nitrendipine in another. Diclofenac reduces verapamil serum levels and raises those of isradipine, but these changes are probably unimportant. 

Indometacin 100 mg daily for a week did not significantly affect the hypotensive effects of nifedipine 20 mg twice daily in 10 patients with mild to moderate essential hypertension. In contrast, in another study, indometacin 100 mg in divided doses over 24 hours was found to raise the mean arterial pressure by 17 to 20 mmHg in 5 out of 8 hypertensive patients taking nifedipine 15 to 40 mg daily. ... 

Spasmolitic - in vitro (rat, aorta), induced contractions by Potassium (IC50 19.8 gM) and phenylephrine 172 (IC50 36.8 gM). Effect not antagonized by indometacin or nifedipine. 

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See also in sourсe #XX -- [ ]

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