Brief Answer: You can try them for a week Detailed Answer: Hello, My full sympathies with you on this issue and I know sinus infections can be a very chronic problem. please don't worry, although levofloxacin and betamethasone nasal irrigations will not interact with your thyroid tissues, but i still doubt there usefulness. However ,you can try them for a week if you like and assess your response, otherwise plain saline irrigation and steam inhalation should be perfectly fine for you. hope i have cleared your doubts thanks

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