Metformin HCL ER

Patient: I do not understand what the hcl does in Metformin HCL ER. My doctor switche4d my medicine from Metformin HCL ER to just Metformin ER and it does not seem to be as effective, can yoiu tell me why? no doctor has the answer and I even asked a pharmacist. thank you.Laura Vieira

Doctor: