Have been on allegra (fexofenadine) d for a day now, theinteract with anything in allegra (fexofenadine) d?

Allegra (fexofenadine) D. Plain Allegra (fexofenadine) probably does not interact with any other medicines. Allegra (fexofenadine) d has 'decongestant'. It helps stuffiness. Decongestants can affect sleep, blood pressure and cause difficulty in urination in people with prostate problems. Read the brochure and don't hesitate to ask questions from the pharmacist for any over the counter medicines.