Dwight asked
How long does Allegra (Fexofenadine) last?
At a glance
- Allegra (fexofenadine) has a fast onset of action, and typically begins working in as little as one hour. For most individuals, each dose will last 24 hours (although 12-hour verions are available as well).
Answer
Allegra (Fexofenadine) is a second generation antihistamine belonging to a class of medications known as H1-receptor antagonists.
Second-generation antihistamines are known for their long duration of action.
Allegra is also in 12-hour versions too, which can be dosed twice daily (60 mg for adults and 30 mg for children).
What Is Allegra?
Allegra is a popular choice for controlling allergy symptoms since it is non-sedating (unlike Benadryl) and lasts much longer than most antihistamines (around 24 hours).
Allegra was first FDA approved as a prescription medicine in 1996 and in 2011, was approved for over-the-counter sale in the same formulations and strengths as available by prescription.[3]
Onset And Duration Of Action
Allegra is taken by mouth and typically begins to work quickly after dosing. The onset of antihistamine effectiveness is usually as fast as 1 hour and can last up to 24 hours... which allows for the once-daily dosing.[4]
While Allegra begins to work quickly, studies show that it takes around 2 to 3 hours to reach maximum concentrations in the blood (for tablets and capsule dosage forms). Liquid fexofenadine reaches maximum concentrations faster, after about an hour.[5]
Additional Allegra Information
When taking fexofenadine, it is generally recommended to avoid grapefruit, orange, and apple juice before or after drug administration since these can reduce how much of the drug is absorbed.
Allegra is available both as the brand name product as well as generically. It is also available in multiple dosage forms. You can find it OTC (Over The Counter) in the following forms:
- Tablet
- Oral Disintegrating Tablet
- Suspension
- Gelcap
- Children's Tablet
References
- ^ Pharmacology of Antihistamines. PubMed
- ^ Selecting optimal second-generation antihistamines for allergic rhinitis and urticaria in Asia. Prescribing Information
- ^ Elsevier ClinicalKey Fexofenadine Monograph. ClinicalKey (Subscription Required)
- ^ Fexofenadine: a review of its use in the management of seasonal allergic rhinitis and chronic idiopathic urticaria. PubMed
- ^ Allegra Prescribing Information
