BRAND NAME: Claritin, Claritin RediTabs, Alavert

DRUG CLASS AND MECHANISM: Loratadine is a long-acting antihistamine. Histamine is a chemical that causes many of the signs that are part of allergic reactions, for example, swelling of tissues. Histamine is released from histamine-storing cells (mast cells) and attaches to other cells that have receptors for histamine. The attachment of the histamine to the receptors causes the cell to be "activated," releasing other chemicals which produce the effects that we associate with allergy. Loratadine blocks one type of receptor for histamine (the H1 receptor) and thus prevents activation of cells by histamine. Unlike most other antihistamines, loratadine does not enter the brain from the blood and, therefore, does not cause drowsiness.
PREPARATIONS: Loratadine tablets (white-to-off-white): 10 mg; Claritin RediTabs are rapidly disintegrating tablets that are round, white-to-off-white, and mint flavored containing 10 mg loratadine. Loratadine also is available as a syrup. The nonprescription form of loratadine, Alavert, is available as a 10 mg tablet.

STORAGE: Tablets should be stored at 2-30°C (36-86°F).

PRESCRIBED FOR: Loratadine is used for the relief of nasal and non-nasal symptoms of various allergic conditions such as seasonal allergic rhinitis. It is also used to treat patients with chronic urticaria, a type of allergic skin rash.

DOSING: Loratadine is generally prescribed once daily. Patients with liver diseases or with reduced kidney function need lower doses than patients with normal liver and kidney function.

DRUG INTERACTIONS: There are no known clinically important drug interactions with loratadine.

PREGNANCY: There are no adequate studies of loratadine in pregnant women. However, studies in animals suggest no important effects on the fetus. Loratadine therefore can be used in pregnancy if the physician feels that it is necessary.

NURSING MOTHERS: Loratadine is secreted in breast milk. Although no side effects have been described in nursing infants whose mothers have taken loratadine, this medication should be used with caution in nursing mothers. Loratadine should not be used in children under the age of 12 years.

SIDE EFFECTS: In studies in which loratadine was compared to a placebo (an inactive tablet which was made to look like loratadine), the rates of side effects with loratadine was no greater than that of the placebo. The most common complaints were headache, tiredness, and dry mouth.