Generic Name

Desloratadine

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Classification

FDA Approved Indications

• Relief of symptoms associated with seasonal allergic rhinitis (hay fever)
• Chronic idiopathic urticaria (hives)

Mechanism of Action

Desloratadine is a selective peripheral H1 receptor antagonist that inhibits the effects of histamine, thereby reducing allergy symptoms.

Dosage and Administration

Adult: 5 mg once daily

Pediatric: 2.5 mg once daily for 6-11 years, 5 mg for 12 years and older

Geriatric: same as adult; no dosage adjustment necessary but caution advised in patients with hepatic impairment

Renal Impairment: Adjust as per creatinine clearance; typically, 5 mg every other day in severe impairment

Hepatic Impairment: Consider starting dose of 5 mg every other day

Pharmacokinetics

Absorption: Well absorbed; peak plasma concentration in 1.5 hours

Distribution: Extensively bound to plasma proteins (~98%)

Metabolism: Metabolized in the liver mainly via CYP2C8 and CYP3A4 enzymes

Excretion: Primarily via urine (about 85%), also feces

Half Life: Approximately 27 hours

Contraindications

• Hypersensitivity to desloratadine or any component of the formulation

Precautions

• Use with caution in hepatic impairment; adjust dosing accordingly
• Potential for drowsiness; caution when operating machinery or driving

Adverse Reactions - Common

• Headache (Uncommon)
• Fatigue (Uncommon)
• Dry mouth (Uncommon)

Adverse Reactions - Serious

• Allergic reactions (e.g., rash, pruritus, swelling) (Rare)
• Drowsiness or sedation (less than with first-generation antihistamines) (Uncommon)

Drug-Drug Interactions

• CNS depressants may enhance sedation (though less common with desloratadine)

Drug-Food Interactions

• No significant interactions reported

Drug-Herb Interactions

• No well-documented interactions

Nursing Implications

Patient/Family Teaching

• Take medication as prescribed, even if symptoms improve.
• Avoid alcohol and other CNS depressants while on medication.
• Report any signs of allergic reactions or severe side effects.

Special Considerations

Black Box Warnings:

• None

Genetic Factors: No specific genetic considerations per current data

Lab Test Interference: Not known to interfere with laboratory tests

Overdose Management

Signs/Symptoms: Sedation, dry mouth, tachycardia, hallucinations in severe cases

Treatment: Supportive care; activated charcoal if ingestion is recent; no specific antidote

Storage and Handling

Storage: Store at room temperature, 20-25°C (68-77°F)

Stability: Stable under recommended storage conditions