Levocetirizine and montelukast are usually given for allergy-related cough and cold symptoms, while levofloxacin is a strong antibiotic meant for confirmed bacterial infections, so they are not directly related in action. In most cases, there is no major drug interaction between these medicines, so they can technically be taken together if there is a real need for all of them. But the important point is whether levofloxacin is actually required in your case, because most cough and cold problems are viral or allergy-based and do not need antibiotics at all. Taking levofloxacin without a clear indication may not help and can instead cause side effects like stomach upset, dizziness, sleep disturbance, or, in some cases, muscle or tendon pain. Levocetirizine can also cause mild drowsiness, so overall, you may feel more tired if multiple medicines are combined. If your symptoms include high fever, thick yellow or green sputum, chest infection signs, or are not improving at all, then a doctor may consider antibiotics. Otherwise, it is safer to avoid starting levofloxacin on your own and get proper medical advice before combining medicines.