Azelastine
"The taste is sharp, bitter, and nearly impossible to cover, but because I could barely breathe out of my nose, I wanted to see if the spray would help.  After three days, the congestion wasn't decreased, and I developed a dull headache which would last all day.  I stopped taking it, waited a few days, and used the spray again to see if the headache was just coincidental, but I got the ache almost instantly.  I have also tried Zicam and Clear and they didn't help either; just to provide comparison, but the allergy season on the east coast has been fairly severe."