Azelastine
"I had a very extreme adverse reaction to  Azelastine.  I took one spray in my right nostril.  Immediately, I had intense nasal burning, terrible pressure over my sinuses and severe headache, muscle spasms in calves and shoulders, drowsiness, increased blood pressure. Days later I developed nerve irritation and occipital neuralgia and dizziness due to pinched nerves from the muscle spasms in my shoulders.   My mouth became extremely dry with a bitter taste but luckily that only lasted a couple of days.  The occipital neuralgia has been the worst part.  It has been almost two weeks and I still have the neuralgia.  Massage and stretching help relieve it temporarily but then the pain comes back."