From the Guidelines
The best antihistamine for most people is a second-generation option like fexofenadine (Allegra), loratadine (Claritin), or desloratadine, which provide 24-hour relief from allergy symptoms with minimal drowsiness. These medications are preferred over first-generation antihistamines due to their lower risk of sedation, performance impairment, and anticholinergic effects 1. When choosing a second-generation antihistamine, it's essential to consider the individual's specific needs and symptoms. For example, cetirizine (Zyrtec) and intranasal azelastine may cause sedation at recommended doses, while fexofenadine, loratadine, and desloratadine do not cause sedation at recommended doses 1.
Some key differences among second-generation antihistamines include:
- Fexofenadine, loratadine, and desloratadine are non-sedating at recommended doses
- Cetirizine and intranasal azelastine may cause sedation at recommended doses
- Loratadine and desloratadine may cause sedation at doses exceeding the recommended dose
- No single second-generation antihistamine has been found to achieve superior overall response rates 1
In patients with allergic rhinitis and concomitant asthma, desloratadine therapy has been shown to improve allergic rhinitis, early bronchial response, asthma symptoms, and reduce the need for beta-agonists 1. Additionally, levocetirizine has been found to decrease both symptoms and improve quality of life in patients with persistent allergic rhinitis and asthma 1.
It's crucial to note that antihistamines are not recommended as first-line treatment for asthma, and inhaled corticosteroids and long-acting bronchodilators should be preferred 1. However, for patients with allergic rhinitis, second-generation antihistamines like fexofenadine, loratadine, or desloratadine are excellent choices, providing effective relief from allergy symptoms with minimal side effects.
From the FDA Drug Label
Fexofenadine hydrochloride, the major active metabolite of terfenadine, is an antihistamine with selective peripheral H1-receptor antagonist activity. The FDA drug label does not answer the question.
From the Research
Antihistamine Options
- Loratadine is a long-acting antihistamine with high selectivity for peripheral histamine H1-receptors and lacks central nervous system depressant effects 2
- It is effective in relieving symptoms of allergic rhinitis and chronic urticaria, with a lower incidence of sedation compared to other antihistamines like azatadine, clemastine, and mequitazine 2
- Loratadine has a quicker onset and longer duration of action compared to terfenadine, making it useful for acute allergic reactions 3
Comparison with Other Antihistamines
- Loratadine is as efficacious as existing antihistamines in relieving symptoms of allergic rhinitis, urticaria, and suppressing wheal formation 3
- Second-generation H1 antihistamines like cetirizine, fexofenadine, desloratadine, and loratadine are recommended for mild intermittent or mild persistent allergic rhinitis 4
- First-generation antihistamines are effective but associated with adverse effects due to lack of selectivity for the histamine H(1)-receptor and ability to bind to cerebral H(1)-receptors 5
Safety and Efficacy
- Loratadine has been found to be safe and efficacious in treating seasonal allergic rhinitis, with a single daily oral dose of 10 mg comparable in efficacy to clemastine 6
- The incidence of sedation with loratadine is comparable to placebo and significantly lower than with clemastine 6
- Loratadine has a low incidence of anticholinergic side effects, comparable to placebo and clemastine 6