On an average drugs like glimmepride are effective in controlling blood sugar for about five years,during which period their effect gradually diminishes and ultimately a stage is reached when they are ineffective in in controlling blood sugar even at highest dose.this stage is popularly called as secondary SU failure.However it is actually due to failure of beta cells in pancreas
It seems that you will be requiring insulin
now and oral anti diabetic drugs will not have much effect on you.
Consult a diabetologist
for the exact treatment.