I can see now why aircon makes sense for those with bad hayfever. It means you can leave the windows closed. I am lucky never to have had hayfever. It sounds awful.
the beauty of it is not only does it serve a purpose for hay fever but the advantage of heating and cooling too. You have to get the aircon with the pollen filters for it to be ultra effective though.
Were they exactly the same? Most supermarkets sell two different own brand antihistamines. One uses the drug cetirizine and the other uses the drug loratidine. One might work better than the other for you. Cetirizine has always worked best for me and is also supposed to be quicker acting.