• There are certain other medications that Allegra-D can interact with (see Allegra-D Drug Interactions).
   
• Allegra-D should not be used with other antihistamines or decongestants.
   
• Although Allegra-D causes drowsiness less often than other antihistamines, it may still make some people tired. Therefore, until you know whether Allegra-D makes you tired, caution should be used before driving a car or operating potentially dangerous machinery.
   
• Allegra-D is a pregnancy Category C medicine, meaning that it could potentially harm your unborn child. If you are pregnant, you should only take Allegra-D if the benefit outweighs the possible risk to your unborn child. Discuss the safety with your healthcare provider before using Allegra-D.
   
• If you are nursing or plan to nurse, it is important to know that Allegra-D passes through your milk. Therefore, if you are taking Allegra-D, it is recommended that you stop until talking your doctor.
   

• Are allergic to Allegra-D, Allegra, fexofenadine, pseudoephedrine, adrenergic agents, or any of the inactive components used in making Allegra-D. Your healthcare provider or pharmacist has a list of the inactive ingredients.
   
• Have narrow-angle glaucoma.
   
• Have urinary blockage or difficulty urinating.
   
• Are taking an MAO inhibitor or have taken an MAO inhibitor within the last 14 days. MAO inhibitors are medicines used to treat depression. Some examples of MAO inhibitors include:

o Isocarboxazid (Marplan^®)

o Phenelzine (Nardil^®)

o Selegiline (Eldepryl^®, EMSAM^®)

o Tranylcypromine (Parnate^®).

• Have severe high blood pressure (hypertension).
   
• Have severe coronary heart disease.