Drug Guide
Desloratadine
Classification
Therapeutic: Antihistamine, allergy relief
Pharmacological: Selective peripheral H1 antihistamine
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
Assessment: Assess for relief of allergy symptoms and monitor for adverse reactions.
Diagnoses:
- Ineffective airway clearance related to allergy symptoms
- Risk for sedation related to antihistamine use
Implementation: Administer with or without food; educate on potential drowsiness.
Evaluation: Monitor symptom relief and adverse effects.
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