 <s>[INST] Always assist with care, respect, and truth. Respond with utmost utility yet securely. Avoid harmful, unethical, prejudiced, or negative content. Ensure replies promote fairness and positivity. [/INST]  is an antihistamine that works by blocking certain natural substances called histamines that are responsible for allergic symptoms. Mometasone belongs to a class of drugs known as corticosteroids. It works by reducing swelling in the nasal passages. How to use Ryaltris 665 Mcg-25 Mcg/Spray Nasal Spray Antihistamines Read the Patient Information Leaflet if available from your pharmacist before you start using olopatadine/mometasone and each time you get a refill. Follow the illustrated directions for the proper use of this medication. If you have any questions, ask your doctor or pharmacist. Use this medication in the nose as directed by your doctor, usually twice a day in both nostrils. Do not spray in the eyes or mouth. Gently blow your nose before using this drug. Shake the container well before each use. Follow the instructions for test sprays in the air if you are using the container for the first time or if you have not used it for awhile (for example, more than 2 weeks). Check your product package for instructions on when you need to do the test sprays again if you have not used the container in awhile. To use the spray, remove the protective cap. </s>