ANTIHISTAMINES AND HERBAL MEDICINES OR DIETARY SUPPLEMENTS
One study found that St John's wort increased the clearance of fexofenadine by 1.6-fold, whereas another study found no clinically relevant effect.
If fexofenadine is less effective in a patient taking regular St John's wort, consider this interaction as a possible cause.
If fexofenadine is less effective in a patient taking regular St John's wort, consider this interaction as a possible cause.