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Diabetic treatment requres fine tuning of diet,exercise, and drugs.
You may be taking oral anti diabetic drugs for years and dose is also maximum there may be secondary failure of thes drugs.
In your case it would be prudent to start a basal insulin to avoid fluctuation in blood Glucose level, and adjust the dose of other antidiabetic
It is also very important to know any complication like nephropathy is there or not.
Please consult a Good Physician /Endocrinologist
and investigate FBS,PPBS,HbA1c, Blood Urea, Serum Creatinine
and Urine Albumin and Kidney Sonography
Depending on result treatment can be adjusted to have good control of diabetes
and avoid variation in sugar level.