Really, this is something you should ask your doctors.
FWIW however (not that much, ask your doctor), a year ago my then 88 year old T2 father was on 3 gliclazide a day, and he took 2 in the morning and 1 at night. However, I got him to reduce his carbohydrates to less than 30g per meal (3 meals per day) and he lost his excess stone and a half of weight, reduced his hba1c down to prediabetic levels, looks infinitely healthier and is now on no diabetic meds whatsoever (on the instruction of his diabetic nurse).
Hence
@xfieldok 's question re diet. As a T2, you don't metabolise carbs well, you have a metabolic disorder where you produce too much insulin in response to an inability to process the carbs in your diet. That typically results in weight gain. Gliclazide solves the problem by making your pancreas produce extra insulin, which sort of works but doesn't address the underlying issue, the carb intolerance.
Assuming you're correctly diagnosed as T2 (a lot of T1s spend their first few years misdiagnosed as T2 until the t2 meds stop working because their insulin production goes too low) the increasing medication route is progressive, from metformin through to gliclazide and various other drugs, ultimately ending in insulin injections.
You might want to consider reducing your carbs as a long term option for your situation, though be aware that if you're on gliclazide you need to be careful, as gliclazide can cause hypos (low blood sugar) if you're not careful. If you're on gliclazide, they should have given you a blood testing meter. I strongly recommend that you use it before and (2 hours) after meals to see how your blood sugar reacts to your diet.
Good luck.
ps and if you're already on a low carb diet, ask them to check the T2 versus T1/LADA diagnosis.
