That could have been me.... I used the Jungle Labs parasite clear tank buddies for my two angels who were suffering from a severe case of IP. It actually DID work quite well - I recommend waiting a week, do a WC and dose again to be safe. Obviously, your water quality will help the fish to recover more rapidly post-medication. The ingredient you want for IP is called metronidazole. My LFS unfortunately is Petco and the only medication containing this ingredient was the Jungle Lab tablets. Plah, of course is much more of an expert then me, but if your gouramis is not eating, the tablets worked IME...
HTH - Good Luck
I am having the same problem with my fish, stringy poo, lost all of it's coloration. It has now stopped eating as well. I just lost another gourami, I'm wondering if it died from the same problems. Symptoms were similar.