Possible food and drug interactions when taking Allegra

Check with your doctor before combining Allegra with erythromycin or ketoconazole. These drugs may increase Allegra's effects.
Allow a little time between a dose of Allegra and antacids such as Maalox that contain aluminum and magnesium. This type of antacid can decrease Allegra's effects.
Allegra-D should never be taken within 2 weeks of using an MAO-inhibitor drug such as the antidepressants isocarboxazid, phenelzine sulfate, and tranylcypromine sulfate. Also check with your doctor before combining it with the following:MecamylamineMethyldopaReserpine
You should also avoid Allegra-D if you have a pacemaker and take digoxin. And you should not combine it with over-the-counter antihistamines and decongestants.
Allegra-D should not be taken with fruit juices; combining the two can induce wheals (small itchy swellings) and rash-like symptoms.