Cetirizine

INTRODUCTION

Indications

Relief of allergic symptoms caused by histamine release, including Seasonal and perennial allergic rhinitis; Chronic urticaria.

Action

Antagonizes the effects of histamine at H₁ receptor sites; does not bind to or inactivate histamine. Anticholinergic effects are minimal and sedation is dose related. Therapeutic Effects: Decreased symptoms of histamine excess (sneezing, rhinorrhea, ocular tearing and redness, pruritus).

Adverse Reactions/Side Effects

CNS: dizziness, drowsiness (significant with doses >10 mg/day), fatigue. EENT: pharyngitis. GI: dry mouth.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Monitor symptoms of seasonal allergies (sneezing, rhinitis, itching eyes, cough) or chronic idiopathic urticaria (rash, hives, itching) to help document benefits of this drug in treating these disorders.

• Assess dizziness and drowsiness that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician, and caution the patient and family/caregivers to guard against falls and trauma.

Interventions

• Guard against falls and trauma (hip fractures, head injury, and so forth). Implement fall-prevention strategies, especially in older adults or if balance is impaired (See Appendix E).

Patient/Client-Related Instruction

• Advise patient about the risk of daytime drowsiness and decreased attention and mental focus. Although the risk of drowsiness is considerably lower with this drug compared to traditional antihistamines, patients should use care if driving or in other activities that require quick reactions and strong concentration.

• Advise patient to avoid alcohol and other CNS depressants because of the increased risk of sedation and adverse effects.

• Instruct patient to report other troublesome side effects, including severe or prolonged dry mouth or upper respiratory tract irritation.

Pharmacokinetics

Absorption: Well absorbed following oral administration.

Distribution: Unknown.

Protein Binding: 93%.

Metabolism and Excretion: Excreted primarily unchanged by the kidneys.

Half-life: 7.4–9 hr (decreased in children to 6.2 hr, increased in renal impairment up to 19–21 hr).

Contraindications/Precautions

Contraindicated in: Hypersensitivity to cetirizine, hydroxyzine, or any component; Lactation: Excreted in breast milk; not recommended for use.

Use Cautiously in: Patients with hepatic or renal impairment (dosage reduction recommended if CCr ≤31 mL/min or hepatic function is impaired); OB/Pedi: safety not established for pregnant women or children <6 mo; Geri: Initiate at lower doses.

Interactions