I think you should limit the maintenance dosage of the enemas to twice a week, and start the process of reducing the oral dosage.
I don't think you should lower any more than one pill at a time, but keep it at that dosage for a month. That, in conjunction with the twice a week enemas.
If all is good after a month, then lower another pill.
Your dosage of the enemas is low...2g. Since you have limited to proctitis....it's a good insurance.