Answer
Aug 19, 2026 - 09:53 AM
Fexofenadine (Allegra) is generally well tolerated and is considered a less-drowsy antihistamine, but side effects can occur.
Common side effects include headache, dizziness, nausea/indigestion, tiredness or drowsiness, stomach discomfort, and occasionally back or limb pain.
Rare but more serious reactions include swelling of the face, lips, tongue or throat, difficulty breathing or swallowing, chest tightness, severe rash/hives, or anaphylaxis. Those symptoms require urgent medical attention.
Since you were asking about taking two Allegra 12 Hour tablets at once, the FDA labeling notes that dizziness, drowsiness, and dry mouth have been reported with fexofenadine overdose.
If you tell me whether you already took two 60-mg tablets at once, I can explain specifically how concerning that dose is and what you should do next.
