Allegra

Al·leg·ra (-lgr)

A trademark for the drug fexofenadine hydrochloride.

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fexofenadine hydrochloride

Allegra, Telfast (UK)

Pharmacologic class: Peripherally selective piperidine, selective histamine₁-receptor antagonist

Therapeutic class: Antihistamine (nonsedating type), second-generation

Pregnancy risk category C

Action

Blocks effects of histamine at peripheral histamine₁-receptor sites, decreasing allergy signs and symptoms

Availability

Capsules: 60 mg

Tablets: 30 mg, 60 mg, 180 mg

⊘Indications and dosages

➣ Seasonal allergic rhinitis; chronic idiopathic urticaria

Adults and children older than age 12: 60 mg P.O. b.i.d. or 180 mg once daily

Children ages 6 to 12: 30 mg P.O. b.i.d.

Dosage adjustment

• Renal impairment

Contraindications

• Hypersensitivity to drug, terfenadine, or their components

Precautions

Use cautiously in:
• renal impairment
• concurrent ketoconazole or erythromycin therapy
• elderly patients
• pregnant or breastfeeding patients
• children younger than age 12 (safety not established).

Administration

• Don't give with apple, orange, or grapefruit juice.
• Don't give antacids within 2 hours of fexofenadine.

Route	Onset	Peak	Duration
P.O.	Within 1 hr	2-3 hr	12-24 hr

Adverse reactions

CNS: drowsiness, fatigue, headache

EENT: otitis media

GI: nausea, dyspepsia

Metabolic: dysmenorrhea

Respiratory: upper respiratory tract infection

Other: viral infection

Interactions

Drug-drug. Antacids containing aluminum and magnesium: decreased absorption and efficacy of fexofenadine

Drug-diagnostic tests. Skin allergy tests: false-negative results

Drug-food. Apple, orange, and grapefruit juice: decreased absorption and efficacy of fexofenadine

Patient monitoring

• Monitor renal function.
• Watch for signs and symptoms of viral infection.

Patient teaching

• Tell patient to stop taking drug 4 days before diagnostic skin tests, to avoid interference with test results.
• Advise patient to report signs or symptoms of viral infection, especially upper respiratory tract infection.
• Caution patient to avoid driving and other hazardous activities until he knows how drug affects concentration and alertness.
• Advise female patient to inform prescriber if she is pregnant or breastfeeding.
• As appropriate, review all other significant adverse reactions and interactions, especially those related to the drugs, tests, and foods mentioned above.