What is the most important information I should know about alavert? Use caution when driving, operating machinery, or performing other hazardous activities. Although unlikely, alavert may cause dizziness or drowsiness. If you experience dizziness or drowsiness, avoid these activities. What is alavert? alavert is an antihistamine. Antihistamines prevent sneezing, runny nose, itching and watering of the eyes, and other allergic symptoms. alavert is used to treat allergies, hives (urticaria), and other allergic inflammatory conditions. alavert may also be used for purposes other than those listed in this medication guide.