John asked
How long does Claritin take to work?
Answer
Claritin (loratadine) is a commonly used allergy medication that is available over the counter. Claritin is indicated to be taken as 10 mg by mouth once daily and it is not recommended to take more than 10 mg over a 24-hour period.
Claritin starts working within 1-3 hours and reaches peak effect between 8-12 hours, but continues to last at least 24 hours in most patients. Although food can increase the amount of drug absorbed, the manufacturer states that the medication can be taken without regard to meals.
Claritin is a part of a medication class known as
antihistamines. Specifically, Claritin is considered to be a second-generation
antihistamine. Other second-generation antihistamines include Allegra
(fexofenadine) and Zyrtec (cetirizine). Claritin was first approved in 1993 as
a prescription medication, but was later approved for over the counter use in
2002.
Does Claritin Cause Drowsiness?
The benefit of second-generation
antihistamines, such as Claritin, is that they are less prone to cause drowsiness. First-generation antihistamines,
such as Benadryl (diphenhydramine) and Dramamine (dimenhydrinate), are known to
cause drowsiness due to their likelihood of crossing the blood-brain barrier. The
least sedating antihistamine is thought to be Allegra. Claritin and Zyrtec are
generally well tolerated, but may cause drowsiness in some people.
How Antihistamines Work:
Antihistamines bind to histamine receptors that are found in
the nose, lungs, eyes, and skin without activating the histamine response. By
binding and changing the shape of the histamine receptor, antihistamines
inhibit histamine from binding and creating its response. Histamine creates an
immune response to essentially attempt to remove the offensive allergen.
Histamine can be triggered by a variety of things including pollen, dust, and
pet dander. Some people are more sensitive to this response and may not even
know what triggers their allergies. Antihistamines are useful in preventing the
immune cascade so common in people suffering from allergies.
