FEXOFENADINE

Medical Diagnosis and Drugs, Medications

FEXOFENADINE
(fex-o-fen'a-deen)
Allegra
Classifications: antihistamine; h₁-receptor antagonist, non-sedating;
Therapeutic: antihistamine; non-sedating h₁-receptor antagonist
Prototype: Loratadine
Pregnancy Category: C

Availability

30 mg, 60 mg, 180 mg tablets; 60 mg capsules; 30 mg orally disintegrating tablet

Action

Competes with free histamine for binding at the H₁-receptor. This competitive antagonism blocks effects of histamine on H₁-receptors in bronchial smooth muscle. This also results in decreased formation of edema, flare, and pruritus that result from histaminic activity.

Therapeutic Effect

Inhibits antigen-induced bronchospasm and histamine release from mast cells. Efficacy is indicated by reduction of the following: nasal congestion and sneezing; watery or red eyes; itching nose, palate, or eyes.

Uses

Relief of symptoms associated with seasonal allergic rhinitis, and chronic urticaria.

Contraindications

Hypersensitivity to fexofenadine or terfenadine; neonates; pregnancy (category C).

Cautious Use

Mild to severe renal and hepatic insufficiency, hypertension, diabetes mellitus, ischemic heart disease, increased ocular pressure, hyperthyroidism, renal impairment, or prostatic hypertrophy; young children.

Route & Dosage

Allergic Rhinitis
Adult/Child (>12 y): PO 60 mg b.i.d. OR 180 mg q.d.
Child (6–11 y): PO 30 mg b.i.d.

Chronic Urticaria
Adult: PO 60 mg b.i.d. OR 180 mg q.d.
Child (2–11 y): PO 30 mg b.i.d.
Infant (>6 mo): PO 15 mg b.i.d.

Renal Impairment
Cl_cr <80 mL/min: reduce to one dose per day

Administration

Oral

Reduce starting dose for those with decreased kidney function.
Do not give within 15 min of an aluminum- or magnesium-containing antacid.
Store at 20°–25° C (68°–77° F). Protect from excess moisture.

Adverse Effects (≥1%)

CNS: Headache, drowsiness, fatigue. GI: Nausea, dyspepsia, throat irritation.

Interactions

Drug: antacids will decrease serum level of fexofenadine. Herbal: St. John's wort will decrease serum level of fexofenadine. Food: Grapefruit juice may decrease efficacy.

Pharmacokinetics

Absorption: Rapidly from GI tract, 33% reaches systemic circulation. Onset: 1 h. Peak: 2–3 h. Duration: At least 12 h. Distribution: 60–70% bound to plasma proteins. Metabolism: Only 5% of dose metabolized in liver. Elimination: 80% in urine, 11% in feces. Half-Life: 14.4 h.

Nursing Implications

Assessment & Drug Effects

Monitor therapeutic effectiveness, which is indicated by decreased nasal congestion, sneezing, watery or red eyes, and itching nose, palate, or eyes.

Patient & Family Education

Note: Drug is well tolerated and causes minimal adverse effects.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

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