What are the contraindications of Allegra (Fexofenadine)?

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Last updated: April 29, 2025View editorial policy

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From the Guidelines

Allegra (fexofenadine) is contraindicated in patients with known hypersensitivity to fexofenadine or any of its ingredients. While generally well-tolerated, certain populations should use Allegra with caution. Patients with decreased kidney function may need dose adjustments as the medication is primarily eliminated through the kidneys 1. Those with phenylketonuria should avoid the orally disintegrating tablet formulations which contain phenylalanine. Pregnant and breastfeeding women should consult healthcare providers before use, though no significant risks have been established 1. Unlike older antihistamines, Allegra doesn't cause significant drowsiness or interact with the cardiac conduction system, making it safer for patients with heart conditions 1. It has minimal drug interactions, though antacids containing aluminum or magnesium can reduce its absorption if taken simultaneously. Patients should take Allegra at least 2 hours before or after antacids for optimal effectiveness. The medication is generally safe for elderly patients and doesn't significantly interact with alcohol, though combining them isn't recommended. Some key points to consider when prescribing Allegra include:

  • Monitoring kidney function in patients with decreased kidney function
  • Avoiding use in patients with known hypersensitivity to fexofenadine or its ingredients
  • Consulting healthcare providers before use in pregnant and breastfeeding women
  • Taking the medication at least 2 hours before or after antacids to optimize effectiveness
  • Being cautious when combining Allegra with other medications that may interact with it. In terms of specific guidance, patients should be advised to:
  • Take Allegra as directed by their healthcare provider
  • Avoid taking Allegra with antacids containing aluminum or magnesium
  • Consult their healthcare provider before taking Allegra if they have decreased kidney function or are pregnant or breastfeeding. Overall, Allegra is a safe and effective medication for the treatment of allergic rhinitis, but it should be used with caution in certain populations and under the guidance of a healthcare provider.

From the FDA Drug Label

CONTRAINDICATIONS Fexofenadine Hydrochloride Tablets are contraindicated in patients with known hypersensitivity to any of its ingredients.

  • Contraindications for Allegra (fexofenadine) include:
    • Known hypersensitivity to any of its ingredients The FDA drug label for Allegra indicates that it is contraindicated in patients with a known hypersensitivity to any of its ingredients 2.

From the Research

Allegra Contraindications

  • There are no direct contraindications mentioned in the provided studies for Allegra (fexofenadine) 3, 4, 5, 6, 7.
  • However, it is noted that fexofenadine should be used with caution in patients with renal impairment, as it can increase the risk of adverse effects 5, 6.
  • Fexofenadine is not recommended for patients with end-stage renal disease (ESRD) due to reduced nonrenal clearance 6.
  • Patients taking P-glycoprotein (P-gp) inhibitors, such as ketoconazole or erythromycin, should be monitored for increased fexofenadine exposure 4, 5.
  • Grapefruit juice and apple juice can decrease the exposure of fexofenadine, particularly the (S)-enantiomer, and should be avoided 7.
  • Combinations of multiple transporters, such as OATP2B1 and P-gp, can facilitate enantioselective disposition of fexofenadine, and caution should be exercised when co-administering drugs that interact with these transporters 7.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

The systemic safety of fexofenadine HCl.

Clinical and experimental allergy : journal of the British Society for Allergy and Clinical Immunology, 1999

Research

ESRD impairs nonrenal clearance of fexofenadine but not midazolam.

Journal of the American Society of Nephrology : JASN, 2009

Research

An update on the clinical pharmacokinetics of fexofenadine enantiomers.

Expert opinion on drug metabolism & toxicology, 2018

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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