Allegra (Fexofenadine) Allergy Tablets
Allegra is an over-the-counter or prescription oral antihistamine containing fexofenadine. It is used in adults and children for allergic rhinitis and chronic urticaria, with very limited central nervous system penetration and no clinically relevant sedation.
- Active ingredients
- Fexofenadine
- Manufacturer
- Sanofi
- Dosage forms
- tablet, oral suspension, orodispersible tablet
- Available dosages
- 30mg, 60mg, 120mg, 180mg
- Category
- Allergy and Antihistamines
What is it?
Allegra is the original brand name for fexofenadine, marketed by Sanofi (originally Hoechst Marion Roussel and then Aventis). It was approved by the United States Food and Drug Administration in 1996 and is supplied as oral tablets, orally disintegrating tablets and oral suspension. Depending on the country, Allegra is sold over the counter or only with prescription. Multiple authorised generics of fexofenadine are available worldwide.
Active ingredients
Each tablet contains fexofenadine hydrochloride as the sole active ingredient at 30mg, 60mg, 120mg or 180mg. Fexofenadine is the active metabolite of terfenadine and is a second-generation H1 antihistamine with very low central penetration.
Forms and dosages
Allegra is administered orally with water and not with fruit juices, which can reduce its absorption. According to the prescribing information, the usual adult and adolescent dose is 60mg twice daily or 180mg once daily for allergic rhinitis, and 60mg twice daily for chronic urticaria. Paediatric dosing is age and weight-based; oral suspension and orodispersible formulations facilitate accurate paediatric administration.
Indications
Allegra is approved in adults and children for the treatment of seasonal allergic rhinitis and chronic idiopathic urticaria. According to international guidelines, it is one of the recommended second-generation antihistamines for first-line treatment of these conditions, particularly when minimal sedation is required. Allegra is not the first-line treatment for severe asthma or anaphylaxis.
How it works
Fexofenadine selectively blocks peripheral H1 histamine receptors, antagonising the effects of histamine on vasodilation, capillary permeability, sensory nerve endings and smooth muscle. Its very low penetration of the blood-brain barrier accounts for the absence of clinically relevant sedation. The drug also lacks significant anticholinergic effects at standard doses.
Frequently asked questions
Why should Allegra not be taken with fruit juice? ▾
Fruit juices such as orange, grapefruit and apple juice inhibit intestinal organic anion-transporting polypeptides that absorb fexofenadine, reducing bioavailability by up to 60%. This may diminish clinical effect. According to the prescribing information, Allegra should be taken with water rather than juice, with a recommended interval of several hours from juice consumption.
Does Allegra cause drowsiness? ▾
Allegra is one of the antihistamines with the lowest reported sedation profile, often preferred when minimal sedation is required, including in commercial drivers and other safety-critical occupations. Mild fatigue or headache may still be reported in some patients. According to the prescribing information, patients should be cautious about activities requiring alertness until they know how the medication affects them.
How is Allegra different from Zyrtec or Claritin? ▾
All three are second-generation antihistamines, but Allegra (fexofenadine) has the lowest reported sedation profile of the three and is often preferred when sedation must be minimised. Zyrtec (cetirizine) has slightly more sedation and a faster onset, while Claritin (loratadine) has minimal sedation and a long half-life. Choice between them is often a matter of individual response. All three are recommended first-line options in international guidelines.
Can children take Allegra? ▾
Yes, in age- and weight-based dosing. Allegra is approved in children from age six in some markets and from age two in others, with paediatric formulations and dose schedules defined in the prescribing information. According to clinical guidelines, paediatric prescribing should be discussed with a paediatrician or pharmacist, particularly in chronic conditions or in young children with renal impairment.
What are the main contraindications for Allegra? ▾
Allegra is contraindicated in known hypersensitivity to fexofenadine or its excipients. Caution is required in significant renal impairment, where dose adjustment may be needed, and in pregnancy and breastfeeding, where data are limited. According to the prescribing information, the medical history and current medication list must be reviewed by a clinician before any prescription, particularly when other allergy or CNS-active medications are already being taken.
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The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.