I take lantus (insulin glargine) 20 units at night and glimeperide 2mg in the morning was 73kgs a year ago now am 88 kgs what can i replace the 2 with?

No easy answer: Your weight gain can be due to many reasons. The improvement in your blood sugar control since being on these medications is probably a major reason. Unfortunately, medications like glimeperide and Insulin promote weight gain, whereas other medications for diabetes such as metformin and glp-1 agonists promote weight loss. You should talk to your doctor about these other possible medications.