Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Taking MAO inhibitors with this medication may cause a serious (possibly fatal) drug interaction. Avoid taking MAO inhibitors (isocarboxazid, linezolid, metaxalone, methylene blue, moclobemide, phenelzine, procarbazine, rasagiline, safinamide, selegiline, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before treatment with this medication. Ask your doctor when to start or stop taking this medication.

Check the labels on all your medicines (such as cough-and-cold products) because they may contain similar ingredients (decongestants such as phenylephrine). Ask your pharmacist about using those products safely.

Loratadine is very similar to desloratadine. Do not use medications containing desloratadine while using loratadine.

This medication may interfere with certain lab tests (such as allergy skin testing), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.