Hi,
Welcome to HCM,
Your father is Diabetic and taking metformin which is good drug for Diabetes type II but hid FBS is still uncontrolled.
Please do not change by yourself to GP1(
Glimepiride) please consult your Physician he/she will adjust your treatment. Metformin belongs to group biguanide and insulin sensitizer useful in type II and GP1 is sulfonyl urea increases insulin secretion it can be combined with metformin but you can do so only after consulting your Physician.
glimepiride(GP1) can cause gastrointestinal tract (GI) disturbance, and rarely
thrombocytopenia,
leukopenia,
hemolytic anemia, and occasionally allergic reactions occur.
He should take care of diet and exercise regularly if he is
overweight try to lose some weight and by chance if he take alcohol or smokes ask him to stop both.
Please monitor FBS,PPBS every month and HbA1c every three months.
Take care.
Good Luck