What is a notable less severe side effect of Fexofenadine?

Fexofenadine is an antihistamine commonly used to relieve allergy symptoms. Among the side effects associated with antihistamines, dry mouth is considered a less severe and more common side effect. This occurs due to the anticholinergic effects that can be seen with certain antihistamines, which can reduce saliva production.

Choosing dry mouth as a notable side effect reflects a common understanding of the drug's profile, as it generally indicates a more benign issue that can often be managed easily by ensuring adequate hydration or using oral moisturizers. In contrast, the other options listed, such as severe fatigue and high blood pressure, imply more serious implications and are not typically associated with Fexofenadine under normal circumstances. Hyperactivity is also not associated with this medication in standard use, making dry mouth the more appropriate choice as a less severe side effect of Fexofenadine.