What is fexofenadine and pseudoephedrine? What is Allegra-D used for?
Allegra-D is a combination of an antihistamine (fexofenadine) and a decongestant (pseudoephedrine). Fexofenadine is an oral, "second generation" antihistamine that is used to treat the signs and symptoms of allergy and hives. It is similar to the other second generation antihistamines loratadine (Claritin), cetirizine (Zyrtec) and azelastine (Astelin).
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 cell to become "activated," releasing other chemicals that produce the effects that we associate with allergy (for example, sneezing).
Fexofenadine blocks one type of receptor for histamine (the H1 receptor) and thus prevents activation of H1 receptor-containing cells by histamine. Unlike the first generation antihistamines, fexofenadine and other second-generation antihistamines do not readily enter the brain from the blood. Therefore, they cause less drowsiness and are called non-sedating antihistamines. Pseudoephedrine causes blood vessels in the nasal passages to narrow (vasoconstrict). Vasoconstriction reduces nasal congestion by preventing fluid from draining from blood vessels into nasal passages. The FDA approved Allegra-D in December 1997.
What brand names are available for fexofenadine and pseudoephedrine?
Is fexofenadine and pseudoephedrine available as a generic drug?
Do I need a prescription for fexofenadine and pseudoephedrine?
What are the side effects of fexofenadine and pseudoephedrine?
Side effects of Allegra-D include stimulation of the
nervous system by pseudoephedrine leading to:
- tremor, hallucinations, and
- convulsions (seizures).
Other important side effects include:
Allergies can best be described as:
What is the dosage for fexofenadine and pseudoephedrine?
Allegra-D usually is taken once or twice daily. The
recommended dose is one 60/120 mg tablet twice daily or one 180/240 mg tablet
once daily. Persons with kidney disease and elderly persons may only need to
take one tablet per day. Allegra-D should be taken without food. It must be used
cautiously in patients with heart (coronary artery) disease and angina, and
diabetes because of the heart-stimulating effects of pseudoephedrine.
Which drugs or supplements interact with fexofenadine and pseudoephedrine?
Allegra-D should not be taken with monoamine
oxidase (MAO) inhibitor drugs such as phenelzine (Nardil) and tranylcypromine (Parnate)
because combining pseudoephedrine with MAO inhibitors can lead to dangerous
increases in blood pressure and other serious side effects. Aluminum containing
antacids (for example, Maalox) reduces the absorption of fexofenadine.
Therefore, aluminum containing antacids and fexofenadine should not be
administered together. Fruit juices (apple, orange, grapefruit) may reduce the
absorption of fexofenadine, andexofenadine should only be administered with
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Is fexofenadine and pseudoephedrine safe to take if I’m pregnant or breastfeeding?
Pseudoephedrine causes birth defects in some animal
species. Additionally, there have been associations between first trimester
exposure to drugs related to pseudoephedrine and fetal malformations, though the
malformations have been primarily minor. Thus, Allegra-D should be used in
pregnancy only if the physician feels that the potential benefit outweighs the
risks. Fexofenadine has not been adequately studied in pregnant women.
Pseudoephedrine is secreted in breast milk. The
American Academy of Pediatrics considers pseudoephedrine to be compatible with
nursing. Fexofenadine has not been adequately studied in women who are
What else should I know about fexofenadine and pseudoephedrine?
What preparations of fexofenadine and pseudoephedrine are available?
Tablets (fexofenadine/pseudoephedrine): 60/120 mg,
How should I keep fexofenadine and pseudoephedrine stored?
Tablets should be stored at room temperature between 15 C – 30 C (59 F – 86 F).