Juice blocks absorption of Allegra ?

[xchocoholic]

http://rx-s.net/weblog/more/fexofenadine_allegra_interactions/

Most food does not interact significantly with fexofenadine; the drug may be administered with or without food. However, some fruit juices appear to impair the absorption of fexofenadine.

Apple juice, orange juice, and grapefruit juice have been reported to decrease the AUC and Cmax of fexofenadine by roughly 60 - 70%, but individual variability in the changes have been noted in various studies.

According to the manufacturer, the bioavailability of fexofenadine is estimated to be reduced by 36% during coadministration with grapefruit or orange juice.

The mechanism of the interaction is proposed to be an inhibition of intestinal P-glycoprotein transport systems by the juices, resulting in decreased systemic drug absorption.

Does anyone know what this means and how it applies to other P-glycoproteins ?

I remember something being said about grapefruit juice and some other medication too ...

Does this kind of cross reaction apply to other foods and supplements too ?

Or is this just a problem for someone who has too much histamine and needs an antihistamine ?

thanks ... x