Hi, My doctor prescribed me Nasla Solution Azelastine HCI . I didn t realize what was happening to as of today. I was hospitalized with a big pain in my head and at the same time my Asthma was activated. The doctors in he hospital made me a MRI, CT scan, and finally a study (which I do not know how to say it in English) It was liquid from the lower of my back. Thanks God all analysis was negative. The story is that I continue with the headrick pain and my face has sweating on it. I just realized that before my hospitalization my cardiology told me to use Azelastine HCI and since I start using it now is when I decided to find out the side affect of this medicine. Just let me know if this could be why I was feeling with the head pain until now. The doctors could not find out in the hospital what was causing me the pain in my head. They thought that it was meningitis, but again thanks God it was not, so they dicided to discharge me. By the way I was in intensive care and to alleviate my pain they gave mi morfina every 4 hours. Please let me know if this that I still have has to be that I m allergic of this medicine.Thanks.