The main side effects of drugs such as antihistamines, which reduce the reaction of the allergen in the body, are dry mouth and especially a tendency to sleep. For this reason, it is recommended to drink plenty of fluids while using these drugs and to take them close to sleep at night. Although systemic side effects of cortisone-containing nasal sprays are extremely rare, bleeding and dryness of the nose may occur, especially due to misuse. In order to prevent this, it will be useful to direct the sprays to the cheeks and squeeze the medicine after putting them into the nose.

 

Source:  http://www.kbb.org.tr