Can allegra (fexofenadine) make you feel jittery?

Jitters with Allegra (fexofenadine) Make sure it isn't Allegra (fexofenadine)-D as the "d" part (pseudoephedrine causes jitters. Allegra (fexofenadine) and other 2nd generation antihistamines (claritin, zyrtec) don't easily go from the blood into the brain so rarely cause sedation and other nervous system problems. Jitteriness is not a listed Allegra (fexofenadine) side-effect though I have seen 1 or 2 patients who develop it with Allegra (fexofenadine) but can tolerate other antihistamies.