Every drug will serve certain mild to severe side effects. Fexofenadine (Allegra) mostly has mild side effects such as nausea, vomiting, muscle discomfort, menstrual cramps, insomnia, stomach upset and dizziness. However, if these above mentioned symptoms aggravates, it is strictly recommended to contact the doctor immediately. Overdoses can also cause side effects such as drowsiness ness and dry mouth, which may or may not be serious.
