Fexofenadine Hydrochloride

Name: Fexofenadine Hydrochloride

Introduction

Second generation antihistamine; active carboxylic acid metabolite of terfenadine (no longer commercially available in the US).1 2 3 18 79 80

Uses for Fexofenadine Hydrochloride

Allergic Rhinitis

Symptomatic relief (alone or in fixed combination with pseudoephedrine hydrochloride) of seasonal allergic rhinitis (e.g., hay fever).1 77 88

Use fixed-combination preparation only when both antihistamine and nasal decongestant activity are desired.77 88

Chronic Idiopathic Urticaria

Treatment of uncomplicated skin manifestations of chronic idiopathic urticaria.1 70 79

Substantially reduces pruritus and the number of wheals.1

Fexofenadine Hydrochloride Dosage and Administration

Administration

Oral Administration

Administer conventional tablets or capsules orally without regard to meals.8

Fixed-combination fexofenadine hydrochloride/pseudoephedrine hydrochloride preparations: Administer orally on an empty stomach with water.77 88 Swallow tablets whole; do not break, crush, or chew.77 88

Dosage

Available as fexofenadine hydrochloride; dosage expressed in terms of the salt.1 77 88

Fixed-combination preparations available as Allegra-D 12 Hour and Allegra-D 24 Hour.77 88 Allegra-D 12 Hour and Allegra-D 24 Hour tablets contain 60 or 180 mg of fexofenadine hydrochloride, respectively, in an immediate-release layer and 120 or 240 mg of pseudoephedrine hydrochloride, respectively, in an extended-release matrix layer that slowly releases the drug.70 77 88

Pediatric Patients

Allergic Rhinitis Oral

Children 6–11 years of age: 30 mg twice daily (as conventional tablets).1

Children ≥12 years of age: 60 mg twice daily or 180 mg once daily (as conventional capsules or tablets).1 2 39

Children ≥12 years of age: 60 mg twice daily (as Allegra-D 12 Hour)77 or 180 mg once daily (as Allegra-D 24 Hour).88

Chronic Idiopathic Urticaria Oral

Children 6–11 years of age: 30 mg twice daily (as conventional tablets).1

Children ≥12 years of age: 60 mg twice daily (as conventional capsules or tablets).1

Adults

Allergic Rhinitis Oral

60 mg twice daily or 180 mg once daily (as conventional capsules or tablets).1 2 39

60 mg twice daily (as Allegra-D 12 Hour)77 or 180 mg once daily (as Allegra-D 24 Hour).88

Chronic Idiopathic Urticaria Oral

60 mg twice daily (as conventional capsules or tablets).1

Special Populations

Hepatic Impairment

Dosage adjustment not necessary.1 2 79

Renal Impairment

Children 6–11 years of age with decreased renal function: 30 mg once daily (as conventional tablets).1

Adults and children ≥12 years of age with decreased renal function: 60 mg once daily (as conventional capsules or tablets or in fixed combination with 120 mg of pseudoephedrine hydrochloride [Allegra-D 12 Hour]).1 2 77 Avoid use of fixed-combination preparation containing 180 mg of fexofenadine hydrochloride and 240 mg of pseudoephedrine hydrochloride (Allegra-D 24 Hour) in patients with renal impairment because of possible risk of pseudoephedrine accumulation.88

Geriatric Patients

Select dosage carefully.1 77 (See Geriatric Use under Cautions.)

Interactions for Fexofenadine Hydrochloride

Minimally metabolized by CYP microsomal enzymes.1

When using fixed-combination preparations containing pseudoephedrine hydrochloride, consider the drug interactions associated with pseudoephedrine.77 88

Specific Drugs and Foods

Drug or Food

Interaction

Comments

Antacids

Decreased fexofenadine concentrations when administered within 15 minutes of an aluminum- and magnesium-containing antacid (Maalox)1

Avoid administering closely in time with antacids containing aluminum and magnesium1 77 88

Erythromycin

Increased absorption and decreased biliary excretion of fexofenadine, resulting in increased fexofenadine concentrations;1 77 88 however, no clinically important adverse effects or changes in the QT interval corrected for rate (QTc) reported1 2 77 79 83 88

Fruit (apple, grapefruit, orange) juices

Possibly reduced bioavailability and systemic exposure of fexofenadine77 88

Administer with water77 88

Ketoconazole

Increased absorption and decreased secretion of fexofenadine, resulting in increased fexofenadine concentrations;1 77 88 however, no clinically important adverse effects or changes in the QTc reported1 2 77 79 83 88

Actions

  • Specific, selective, histamine H1-receptor antagonist.1 2 3 18 19 20 22 80

  • Lacks cardiotoxic potential of terfenadine15 16 17 36 66 67 80 since it does not block the potassium channel involved in repolarization of cardiac cells (i.e., blockade of the delayed rectifier potassium current IK).1 8 16 36 66 67 80

  • No appreciable anticholinergic,1 2 77 80 88 antidopaminergic,2 or α- or β-adrenergic blocking1 77 88 effects at usual antihistaminic doses in pharmacologic studies.

  • In clinical studies, incidence of CNS effects (e.g., sedation, EEG disturbances, impaired psychomotor performance) associated with fexofenadine is similar to that with placebo and less than that with first generation antihistamines (e.g., chlorpheniramine, clemastine, diphenhydramine, triprolidine).1 70

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