Cetirizine doesn't cure sinusitis nor alleviate nasal congestion.  If you have runny nose, nasal drip or sneezing it can reduce these symptoms though.  Depending of the rest of your symptoms or health condition, GeloMyrtol sounds like a better option for you :  it cuts phlegm in smaller pieces so it can be evacuated and in certain case, it prevents symptoms to evoluate into bacterial sinusitis.  It is taken 1 tablet 3 times a day with meals