From the Guidelines
Clarinex (desloratadine) is a suitable option for treating allergy symptoms, with a standard adult dose of 5 mg once daily, as it does not cause significant drowsiness at recommended doses, according to the most recent evidence 1.
Key Points to Consider
- Clarinex works by blocking histamine receptors, preventing the allergic response without causing significant drowsiness compared to older antihistamines.
- The medication is typically taken without regard to meals, and relief usually begins within an hour and lasts 24 hours.
- Unlike first-generation antihistamines, Clarinex doesn't significantly cross the blood-brain barrier, resulting in minimal sedation.
- Common side effects include headache, dry mouth, and fatigue.
- Patients should inform their doctor about other medications they're taking, as interactions can occur.
- Clarinex is contraindicated in those with hypersensitivity to the drug and should be used cautiously in patients with liver or kidney impairment.
Comparison with Other Antihistamines
- Among the newer, nonsedating antihistamines, no single agent has been conclusively found to achieve superior overall response rates 1.
- Fexofenadine, loratadine, and desloratadine do not cause sedation at recommended doses, while loratadine and desloratadine may cause sedation at doses exceeding the recommended dose 1.
- Cetirizine and intranasal azelastine may cause sedation at recommended doses, with cetirizine 10 mg associated with mild drowsiness in 13.7% of patients aged 12 years, compared to 6.3% with placebo 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Clarinex (Desloratadine) Overview
- Desloratadine, also known by the brand name Clarinex, is a nonsedating, peripheral histamine H(1)-receptor antagonist used to treat seasonal allergic rhinitis (SAR), perennial allergic rhinitis (PAR), and chronic idiopathic urticaria (CIU) 2.
- It has a rapid onset of effect and sustained efficacy over a 24-hour dosage interval, as demonstrated in placebo-controlled trials 2.
Efficacy and Safety
- Desloratadine has been shown to be effective in reducing nasal and ocular symptom severity, itching, and wheals, as well as improving sleep and daily activity in patients with SAR and CIU 3.
- It is generally well tolerated, with an overall incidence of adverse events similar to that of placebo 2, 3.
- Common adverse events associated with desloratadine include fatigue, headache, dry mouth, and nausea 3.
Comparative Studies
- A study comparing desloratadine with cetirizine found that cetirizine had significantly greater suppression of skin reactivity to histamine during 24 hours after a single dose 4.
- Another study comparing desloratadine with levocetirizine in patients with cedar pollen-induced allergic rhinitis found that both drugs were effective in controlling symptoms, but with no statistically significant difference between the two drugs 5.
- A network meta-analysis of randomized controlled trials found that cetirizine was the most efficacious treatment for allergic rhinitis compared with loratadine, montelukast, and desloratadine 6.
Clinical Use
- Desloratadine can be administered without regard to concurrent intake of food and grapefruit juice, and has negligible potential for drug interactions mediated by several metabolic systems 2.
- It does not cause sedation or prolong the corrected QT (QTc) interval, making it a suitable option for patients with certain medical conditions 2.