Allegra D and Claritin D are both used to treat allergic rhinitis, or hay fever symptoms with sinus congestion, according to Drugs.com. Both drugs use the combination of an antihistamine and decongestant to address the symptoms of sneezing, a runny nose, congestion, eye irritation and postnasal drip. Consult with an allergist to determine the best treatment approach.
Both drugs use the same decongestant drug, pseudoephedrine, to treat nasal congestion. Pseudoephedrine works by restricting blood flow to the sinus cavity, reducing inflammation. This drug can increase a person's heart rate and make the user feel excited or irritable. Both drugs are available in 12 or 24 hour doses, according to Drugs.com. They both use an antihistamine that is classified as non-sedating.
Allegra D's active antihistamine ingredient is fexofenadine, while Claritin D uses loratadine. Fexofenadine is not for everyone and should not be administered to children under 2 without a doctor's recommendation, according to the National Library of Medicine. Allegra D is acquired by prescription only, while Claritin D is available over-the-counter. In some states Claritin D is kept behind the counter at pharmacies because of the pseudoephedrine component.
The function of both medications is two-fold. The function of fexofenadine and loratadine is to block the body's ability to produce histamine, the hormone that causes allergy symptoms. Taking either of these medications will inhibit the mast cells in the body from over-producing histamine, according to Drugs.com. The decongestant ingredient is for the purpose of reducing nasal congestion so the user can breathe normally.
According to the National Library of Medicine, Allegra D can cause dizziness, headaches, vomiting, pain in the limbs, coughing, general pain, hives, rashes, hoarseness, difficulty breathing, diarrhea and dizziness.
Claritin D side effects include dry mouth, nausea, constipation, loss of appetite, dizziness, ringing in the ears, blurred vision, restlessness, skin rash, fast heartbeat, easy bruising and mental confusion, according to Drugs.com.
In rare cases, a severe allergic reaction may occur with either medication. If someone experiences swollen lips or face, difficulty breathing or extreme lightheadedness, he should seek immediate medical attention.
Claritin D is less expensive and time-consuming to obtain because it is available over-the-counter. Many generic medications are available with the same active ingredients as Claritin D. Allegra D is more expensive than Claritin D and has one generic counterpart currently available according to Drugs.com..