What is desloratadine, and how does it work (mechanism of action)?

Desloratadine is an oral, long-acting antihistamine that is similar chemically to loratadine (Claritin). It is used to treat the symptoms caused by histamine. Histamine is a chemical that is responsible for many of the signs and symptoms of allergic reactions, for example, swelling of the lining of the nose, sneezing, and itchy eyes. Histamine is released from histamine-storing cells (mast cells) and then attaches to other cells that have receptors for histamine. The attachment of the histamine to the receptors causes the cells to be "activated," releasing other chemicals which produce the effects that we associate with allergy. Desloratadine blocks one type of receptor for histamine (the H1 receptor) and thus prevents activation of H1 receptor-containing cells by histamine. Desloratadine does not readily enter the brain from the blood and, therefore, causes less drowsiness (sedation). It is a member of a small family of non-sedating antihistamines which includes loratadine (Claritin), cetirizine (Zyrtec), fexofenadine (Allegra), and levocetirizine (Xyzal). Desloratadine was approved by the FDA in December 2001.

What brand names are available for desloratadine?

Clarinex, Clarinex Reditabs

Is desloratadine available as a generic drug?


Do I need a prescription for desloratadine?


What is desloratadine used for?

Desloratadine is used to treat allergies and hives (chronic urticaria) in adults and children 12 years of age and older.

What are the side effects of desloratadine?

The most common side effects of desloratadine are:

What is the dosage for desloratadine?

The recommended dose for adults and children 12 years or older is 5 mg daily.

For children 6 to 11 years of age the dose is 2.5 mg of the syrup or 2.5 mg of the RediTabs once daily.

Children 12 months to 5 years old should receive 1.25 mg of the syrup once daily and children 6 to 11 months old are treated with 1 mg of syrup once daily.

Desloratadine can be taken with or without food.


Allergies can best be described as: See Answer

Which drugs or supplements interact with desloratadine?

Ketoconazole (Nizoral, Extina, Xolegel, Kuric), erythromycin, azithromycin (Zithromax), fluoxetine (Prozac), and cimetidine (Tagamet) increase blood levels of desloratadine by reducing the elimination of desloratadine by liver enzymes.

Is desloratadine safe to take if I'm pregnant or breastfeeding?

Desloratadine has not been studied in pregnant women.

Desloratadine passes into breast milk and should therefore be used with caution in women who are breastfeeding.

What else should I know about desloratadine?

What preparations of desloratadine are available?

Tablets: 5 mg. Orally Disintegrating (RediTabs): 2.5 and 5 mg. Syrup: 0.5 mg/1mL

How should I keep desloratadine stored?

Tablets and syrup should be stored at 25 C (77 F).


Desloratadine (Clarinex, Clarinex Reditabs) is a medication used to treat allergies and hives (chronic urticaria) in adults and children 12 years of age and older. Review side effects, drug interactions, warnings and precautions, and patient safety information prior to taking any medication.

Treatment & Diagnosis

Medications & Supplements

Prevention & Wellness


Could I Be Allergic? Discover Your Allergy Triggers See Slideshow

Health Solutions From Our Sponsors

FDA Logo

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically Reviewed on 8/22/2019
FDA Prescribing Information