The response to vitamin K antagonists (VKAs) is determined by many different factors like age, weight, height, vitamin K intake and genetic polymorphisms [1]. The proton pump inhibitors (PPIs) omeprazole and esomeprazole may enhance the effect of VKAs by inhibition of the hepatic metabolism of coumarins [2]. Some isolated cases have been reported of clinically significant elevated INRs in patients concomitantly using omeprazole and phenprocoumon, a VKA frequently used in Europe [3].Practical experience suggests an interaction between omeprazole or esomeprazole and phenprocoumon, but scientific evidence is still lacking.

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Keywords drugs, esomeprazole, medication, omeprazole, pharmacology, vitamin K antagonists
Persistent URL dx.doi.org/10.1111/j.1365-2125.2012.04295.x, hdl.handle.net/1765/38381
Journal British Journal of Clinical Pharmacology
Citation
Verhoef, T.I, Zuurhout, M.J.L, van Schie, R.F.M, Redekop, W.K, van der Meer, F.J.M, le Cessie, S, … Maitland-van der Zee, A-H. (2012). The effect of omeprazole and esomeprazole on the maintenance dose of phenprocoumon. British Journal of Clinical Pharmacology, 74(6), 1068–1069. doi:10.1111/j.1365-2125.2012.04295.x