I Am A Diabetic Person Having Insulin (huminsuline 30/70) Around

I am a diabetic person having Insulin (huminsuline 30/70) around 50 units a day and having losartan Potassium 50 mg 1 tablet a day . Presently i have some muscular problem in my lower leg due to which I can not walk longer as my muscle starts paining and I must stop for 5-10 minutes for recovery. When I consulted doctor he asked me to do Doppler sonography and suggested me to take levocaritine 500 twice a day and mecobalamin 1500 once in a day. Please suggest if line of treatment is ok or suggest me for another treatment??? appreciate your input