I became allergic to all sorts of allergy medications, especially anything with sudafed-like ingredients. I used to take sudafed for allergies and just suddenly had adverse reactions to it. I quit taking any form of allergy or cold medications about 8 years ago and I couldn't believe it. My allergies actually got better!
Now I use sinus irrigation with normal saline and I take quercetin. As I have had arthritis type symptoms I also take supplements for anti-inflammatory, which in turn also helps my allergies.
I rarely ever get a cold but if I do, I just let it run its course with no medications. I do still use the sinus irrigation, and immune boosting supplements, plus lots and lots of water. My rare colds only last about 1-2 days with this method. I really think that medications prolong a cold.