Before using Allegra, tell your doctor if you are allergic to any drugs, or if you have kidney disease.
Fruit juices and certain antacids can make it harder for your body to absorb Allegra. Take the disintegrating tablet on an empty stomach, at least 1 hour before or 2 hours after a meal.
There may be other drugs that can affect Allegra. Tell your doctor about all the prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor.
Stop using this medication and get emergency medical help if you think you have used too much medicine, or if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Tell your doctor if your symptoms do not improve, or if they get worse after you start taking Allegra. Never take more of the medication than your doctor has prescribed.