I’ve been suffering from IC for 5 years now and for some odd reason Nitrofurantoin/
Macrobid seems to work well
for me, even when my urine culture comes back negative. I take it (100 mg X 2 for 10 days) when my IC flares and within a few days the symptoms are essentially gone. They often come back 3-5 months later, but at least it works temporarily.
My doctors have no idea why this medication works, but it’s been working pretty consistently for the past 3-4 years now.