If you are taking the over-the-counter product to self-treat, read all directions on the product package before taking this medication. If you have any questions, consult your pharmacist. If your doctor has prescribed this medication, take it as directed.

Take this medication by mouth on an empty stomach (at least 1 hour before or 2 hours after a meal). Take this medication with water. Do not take with fruit juices (such as apple, grapefruit, or orange) since they may decrease the absorption of this drug.

Swallow the tablets whole. Do not crush or chew the tablets. Doing so can release all of the drug at once, increasing the risk of side effects.

The dosage is based on your medical condition and response to treatment. Do not increase your dose or take this medication more often than directed.

Do not take antacids containing aluminum and magnesium within 2 hours of taking this medication. These antacids can decrease the absorption of fexofenadine.

Tell your doctor if your symptoms do not improve after 1 week, if they worsen, or if they occur with a fever.