This is a two-arm randomized parallel study. Patients who will be meeting the above-mentioned criteria and agree to take part in the study, were asked to sign an informed consent prior conducting the study.

The whole study protocol were presented to the local institutional review board (IRB).

Inclusion Criteria:

• Adult patients (age above 18)
• Undergoing elective PCI

Exclusion Criteria:

1. Hypersensitivity to metformin or any component of the formulation
2. Patients with current or any history taking metformin either for diabetes mellitus or any other reason such as polycystic ovarian syndrome.
3. Patients diagnosed with type 1 or 2 diabetes mellitus.
4. Any oral or injectable hypoglycemic therapy (e.g. insulin, sulfonylureas)
5. Severe renal dysfunction (eGFR less than 30 mL/minute/1.73 m2 ) from any cause, including shock or septicemia; acute or chronic metabolic acidosis with or without coma (including diabetic ketoacidosis).
6. Treatment with systemic glucocorticoids within 3 months of randomization (due to its potential effect on plasma glucose and HbA1c levels).
7. Metabolic acidosis (total CO 2 below the laboratory lower limit of normal on most recent blood chemistry panel).
8. Need for coronary artery bypass grafting.
9. Participation in other clinical trial in the 30 days before enrollment.
10. The existence of a life-threatening disease with a life-expectancy of less than 6 months.