I Have Always Understood Otrivin To Be A Drug Of

I have always understood Otrivin to be a drug of last resort, due it 'rebound' etc. But I am in the throes of a chronic sinus infection. My doctor suggested Avamys ( Fluticasone Furoate) once daily for 30 days. Plus an antibiotic - aurocefuroxime. I took one tablet this evening. Not thrilled with taking them of course, but in need of help. For relief, should I also use Otrivin? I see a few names that seem like they might contra-indicated....thank you.