Some patients being treated with Levrix may experience somnolence / drowsiness, tiredness and exhaustion. If you are intending to drive, engage in potentially hazardous activities or use machines you are therefore advised first to wait and observe your response to the medicine. However, special tests have revealed no impairment of mental alertness, the ability to react or the ability to drive in healthy test persons after taking Levocetirizine in the recommended dosage.