Allegra, also called Fexofenadine, is an antihistamine, or an H1 Receptor. It is used to treat hay fever, and hives. Allegra works by blocking the effects of a substance called histamine, which is naturally produced by the body.
Be sure to tell your doctor of any allergies you have whether it is to medication or food, preservatives, or dyes. Also, tell your doctor of any other medications you are taking, including vitamins and supplements, and any medical conditions you may have.
If you miss a dose of this medicine, take it as soon as you remember, unless it is almost time for your next dose. Do NOT double doses.
Tell your doctor immediately if any of the following side effects occur: chest tightness ; feeling of warmth, redness of the face, neck, arms and occasionally, upper chest; large, hive-like swelling on face, eyelids, lips, tongue, throat, hands, legs, feet, sex organs; shortness of breath, or difficult or labored breathing.
Let your doctor know if you have bothersome or continuing: back pain; body aches or pain; chills; coughing; difficulty in moving; dizziness; drowsiness; ear congestion; earache; fever; headache; joint pain; loss of voice; muscle aching or cramping; muscle pains or stiffness; nasal congestion; nausea; pain in arms or legs; pain or tenderness around eyes or cheekbones; painful menstrual bleeding; ringing or buzzing in ears; runny or stuffy nose; sneezing; sore throat; stomach upset; swollen joints; unusual feeling of tiredness or weakness; or a viral infection (such as cold and flu).
The molecular weight is 538.13 and the empirical formula is C32H39NO4•HCl.
Fexofenadine hydrochloride is a white to off-white crystalline powder. It is freely soluble in methanol and ethanol, slightly soluble in chloroform and water, and insoluble in hexane. Fexofenadine hydrochloride is a racemate and exists as a zwitterion in aqueous media at physiological pH.
Fexofenadine hydrochloride, the active ingredient of ALLEGRA, is a histamine H1-receptor antagonist with the chemical name (±)-4-[1 hydroxy-4-[4-(hydroxydiphenylmethyl)-1-piperidinyl]-butyl]-a, a-dimethyl benzeneacetic acid hydrochloride.
It has the following chemical structure: