desloratadine, Clarinex

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GENERIC NAME: desloratadine

BRAND NAME: Clarinex

DRUG CLASS AND MECHANISM: 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.



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

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

PRESCRIBED FOR: Desloratadine is used for the treatment of allergies and chronic urticaria (hives) in adults and children 6 months of age or older.

DOSING: 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.

DRUG INTERACTIONS: 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.

PREGNANCY: Desloratadine has not been studied in pregnant women.

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

SIDE EFFECTS: The most common side effects of desloratadine are headache, dizziness, nausea, weakness, sore throat, dry mouth, muscle pain, painful menstruation, and sleepiness.

Reference: FDA Prescribing Information

Last Editorial Review: 4/24/2012

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