DRUG INTERACTIONS: Cimetidine (Tagamet), by decreasing the elimination of metformin from the body, can increase the amount of metformin in the blood by 40%. This may increase the frequency of side effects from metformin.
metformin (Glucophage, Glucophage XR, Glumetza, Fortamet, Riomet) - drug class, medical uses, medication side effects, and drug interactions by MedicineNet.com
I also second a doctor visit for Kim. You are in your 40's with Type 2 diabetes. Any doctor worth two cents would applaud your proactiveness.