Study: NCT02548741

Intervention type: DRUG
Group type: ACTIVE_COMPARATOR
Intervention: Metformin Hydrochloride (500-mg capsule)
Description: Metformin hydrochloride tablets (500-mg) are manufactured by Heritage Pharma INC. Noha Ashy \& David Lee will ground the tablets and put them in capsules to avoid differentiation between treatment and placebo. Using USP 797 compounding standers, Noha Ashy \& David Lee will package the capsules to conceal it from the participants and other investigators. Compounding will take place at the lab, College of Pharmacy (Darchman building, 2nd floor), University of Arizona. New empty capsules (size 0, ½ blue-opaque and ½ white-opaque capsule which will be supplied by Letco Medical) will be provided to the treatment (metformin hydrochloride) arm participants that are similar to the placebo (comparator) capsules in term of color and size to conceal placebo from the investigators and participants.

Intervention type: DRUG
Group type: PLACEBO_COMPARATOR
Intervention: Calcium carbonate (placebo)
Description: Investigators will use powder of calcium carbonate as filler of placebo capsules. Placebo capsules (size 0,½ blue-opaque and ½white-opaque capsule which will be supplied by Letco Medical),will be provided to the comparator arms' participants that are similar to the metformin hydrochloride capsules in term of color and size to conceal placebo from the investigators and participants.Using USP 797 compounding standers, Noha Ashy \& David Lee will package the capsules to conceal it from the participants and other investigators. Compounding will take place at the lab, College of Pharmacy (Darchman building, 2nd floor), University of Arizona.

Intervention type: OTHER
Group type: PLACEBO_COMPARATOR
Intervention: Glucometer (One Touch glucometer), strips and lancets
Description: Investigators will provide glucometer (One Touch glucometer), strips and lancets to the treatment and placebo groups. They will be provided to patients who never had glucometer before enrolling to our study.Also, a logbook will be provided to each participant to record their blood sugar measurements at home.

Intervention type: OTHER
Group type: ACTIVE_COMPARATOR
Intervention: Glucometer (One Touch glucometer), strips and lancets
Description: Investigators will provide glucometer (One Touch glucometer), strips and lancets to the treatment and placebo groups. They will be provided to patients who never had glucometer before enrolling to our study.Also, a logbook will be provided to each participant to record their blood sugar measurements at home.

Intervention type: OTHER
Group type: OTHER
Intervention: Urine container for 24-hour urine collection
Description: During visit 2 (day 0) and visit 3 (day 42), urine container will be provided to the study participant for 24-hour urine collection. Patient will be instructed to bring the container back to the collaboratory. Investigators will transfer the urine container to Dr.Lau's lab to measure the IMZ concentration/content.

Intervention type: OTHER
Group type: PLACEBO_COMPARATOR
Intervention: Urine container for 24-hour urine collection
Description: During visit 2 (day 0) and visit 3 (day 42), urine container will be provided to the study participant for 24-hour urine collection. Patient will be instructed to bring the container back to the collaboratory. Investigators will transfer the urine container to Dr.Lau's lab to measure the IMZ concentration/content.

Intervention type: OTHER
Group type: ACTIVE_COMPARATOR
Intervention: Urine container for 24-hour urine collection
Description: During visit 2 (day 0) and visit 3 (day 42), urine container will be provided to the study participant for 24-hour urine collection. Patient will be instructed to bring the container back to the collaboratory. Investigators will transfer the urine container to Dr.Lau's lab to measure the IMZ concentration/content.