Those symptoms sound more hex which droncit/drontal/adtape is not usually used for this. Droncit/prazi ie is used primarily for external gill flukes and sometimes tapeworm. The primary symptoms of this would be discus scratching, coughing, spitting food and general malaise.
Hex on the other hand is an internal protozoan parasite, the symptoms being weight loss, dark appearance stringy white faeces, disinterest in food, turning on their sides. Hex can be treated with metronidazole and can particularly affect discus and angel fish, fry are particularly susceptible, do you keep angels in your tank with your discus?
I suggest getting both meds if possible, metronidazole (also known as flagyl) is hard to get hold of unfortunately but if you take a printout to your vet of the symptoms sometimes it can be prescribed. Good luck!