It is typically required to reevaluate your condition rather than just switching tablets on your own if you are no longer able to control your blood sugar or symptoms with Citapin 500 mg twice a day. Doctors may choose to add another medicine, such as sitagliptin, glimepiride, or more current options, or adjust the dosage according on your weight, food, and reports. This happens when insulin resistance or diabetes cause the body to gradually become less sensitive. Instead of taking medication on your own, please see your doctor for a blood test so they can safely adjust your treatment.