As with any medicine, side effects are possible with Allegra (fexofenadine hydrochloride); however, not everyone who takes the drug will have problems. In fact, most people tolerate it well. If side effects do occur, in most cases, they are minor, meaning they require no treatment or are easily treated by you or your healthcare provider.
Common Side Effects of Allegra
Allegra has been studied extensively in clinical trials. In these studies, side effects are always documented and compared to symptoms that occur in a similar group of people not taking the medicine. This way, it is possible to see what side effects occur, how often they appear, and how they compare to the group not taking the medicine.
Based on these studies, the most common side effects of Allegra experienced by adults or children include:
Vomiting - in up to 12 % of people
Headache - up to 10.3 %
Coughing - up to 3.8 %
Diarrhea - up to 3.7 %
Respiratory tract infection, such as the common cold or flu - up to 2.9 %
Drowsiness or fatigue - up to 2.8 %
Back pain - up to 2.5 %
Middle ear infection (otitis media) - up to 2.4 %
Fever - up to 2.4 %
Dizziness - up to 2.1 %
Drowsiness - up to 1.3 %
Indigestion - up to 2.1 %
Arm or leg pain - up to 2.1 %.