Allegra-D 24 Hour and Alcohol/Food Interactions

Both pseudoephedrine and caffeine can increase blood pressure and heart rate, and combining them may enhance these effects. Talk to your doctor before using these medications, especially if you have a history of high blood pressure or heart disease. You may need a dose adjustment or more frequent monitoring by your doctor to safely use both medications. Contact your doctor if your condition changes or you experience increased side effects. It is important to tell your doctor about all other medications you use, including vitamins and herbs. Do not stop using any medications without first talking to your doctor.

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GENERALLY AVOID: Coadministration with large amounts of certain fruit juices, including grapefruit, orange and apple, may decrease the oral bioavailability of fexofenadine. The proposed mechanism is inhibition of drug efflux via intestinal organic anion transporting polypeptides (e.g., P-glycoprotein), of which fexofenadine is a substrate. In a five-way crossover study with 10 healthy volunteers, 1/4-strength grapefruit juice, grapefruit juice, orange juice and apple juice (300 mL with drug administration and 150 mL every 1/2 hour for up to 3 hours, total volume 1.2 L) reduced the mean area under the plasma concentration-time curve (AUC) of a 120 mg dose of fexofenadine by 23%, 67%, 72% and 77%, respectively, compared to water. Mean peak plasma concentration (Cmax) was similarly affected. The clinical significance of these changes is unknown. However, results from studies using histamine-induced skin wheals and flares found that the size of wheal and flare was significantly larger when fexofenadine was administered with either grapefruit or orange juices compared to water.

MANAGEMENT: To maximize plasma levels and therapeutic effects, fexofenadine should be taken with water. In addition, patients should refrain from consuming large amounts of grapefruit, orange, or apple juice.