Would macrobid help a sinus infection?

No! Macrobid is specifically for urinary tract infections. It will not work on sinus.I dont know for sure why but I've always been told it will only work in the urinary tract and no where else. If someone is on this for a UTI and develops an infection elsewhere they have to have a second antibiotic for the other infection.

Macrobid is for bacterial infections, so it probably will. Also get some(name brand) Ocean Spray, & rinse out your sinus as directed on the label. Really helps. An old fashioned doctor told me one time forget the antibiotics, & use a Q-tip to put a very small dab of vaseline as high up the nostril as possible for my sinus infection. It worked! I still do this today as I am always getting them from my allergies. After I put in the vaseoline I rub each each side of my nose (usually before bed). Hope this helps, & good luck.