Allegra Side Effects

Every medication has the potential of causing side effects. Side effects are undesirable health problems that occur as a result of taking a particular medication. The cases of adverse events, which included drowsiness was not dose-related and was similar across subgroups defined by age, gender, and race. Listed are the most common side effects associated with the medication.

In adults ages 12 and older with seasonal allergic rhinitis taking 180 mg fexofenadine once daily:

• Headache
• Upper respiratory tract infection
• Back Pain

In adults with seasonal allergic rhinitis taking 60 mg fexofenadine twice daily:

• Viral infection
• Nausea
• Dysmenorrhea (painful menstrual cramps)
• Drowsiness
• Dyspepsia (indigestion)
• Fatigue

In children ages 6-12 with seasonal allergic rhinitis taking 40 mg fexofenadine twice daily:

• Headache
• Accidental injury
• Coughing
• Fever
• Pain
• Otitis media
• Upper respiratory tract infection

In adults ages 12 and older with chronic idiopathic urticaria taking 60 mg fexofenadine twice daily:

• Back pain
• Sinusitis
• Drowsiness

Interaction with other Drugs

Interactions with Antacids
The interaction of fexofenadine hydrochloride within an antacid containing aluminium and magnesium for short time decreased fexofenadine AUC by 41% and cmax by 43%. Allegra should not be taken closely after or before the aluminum and magnesium containing antacid.

Interaction with Erythromycin and Ketoconazole
Fexofenadine either with ketoconazole or erythromycin leads to increased concentrations of fexofenadine. Fexofenadine had no such result on either erythromycin or ketoconazole. No differences in adverse events or the interval were observed when subjects were administered fexofenadine hydrochloride alone or in combination with either ketoconazole or erythromycin. The changes in plasma levels were within the levels achieved in adequate and well-controlled situations. The mechanism of these interactions has been evaluated in vitro, in situ, and in vivo models. These studies indicate that co-administration enhances fexofenadine gastrointestinal absorption. This observed increase in bio-availability of fexofenadine may be due to transport-related effects, such as p-glycoprotein and also suggest that in enhancing absorption, ketoconazole decreases fexofenadine, gastrointestinal secretion, while erythromycin may also decrease the billary excretion.

Interactions with Fruit Juices
Fruit juices such as grapefruit, orange and apple decrease the bioavailability and the degree of exposure to fexofenadine. Based on the analysis of pharmacokinetics, the availability of fexofenadine decreased by 36 percent. Therefore, to maximize the effects of fexofenadine, it is recommended that Allegra must be taken along with water.