Patient X have nifedipine SR 30mg OM, Lovastatin 20mg ON, Acarbose 100mg TDS, Glipizide 10mg BD, Salbutamol 2 puffs PRN and beclomethasone 200mcg BD.

Doctor order discontinue glipizide 10mg, start metformin 500mg BD and to start SC Actrapid based on sliding scale and SC insulatard 25 units BD.

Why doctor order discontinue?