fexofenadine and pseudoephedrine, Allegra-D
Omudhome Ogbru, PharmD
Omudhome Ogbru, PharmD
Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.
Medical and Pharmacy Editor:
GENERIC NAME: fexofenadine and pseudoephedrine
BRAND NAME: Allegra-D
DRUG CLASS AND MECHANISM: 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.
GENERIC AVAILABLE: Yes
PREPARATIONS: Tablets (fexofenadine/pseudoephedrine): 60/120 mg, 180/240 mg
STORAGE: Tablets should be stored at room temperature between 15-30 C (59-86 F).
PRESCRIBED FOR: Allegra-D is used for the temporary relief of runny nose, sneezing, and nasal stuffiness from the common cold. It also is used for the relief of nasal and non-nasal symptoms of various allergic conditions such as seasonal allergic rhinitis. Allegra-D may be used in bronchitis, sore throat (pharyngitis), and for inflamed and congested sinuses (sinusitis).
DOSING: 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.
DRUG INTERACTIONS: 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 water.
PREGNANCY: 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.
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