BUN is a waste product of the body. They monitor that and creatinine clearance to see your kidney function status. If you have elevated levels in the blood, that means your kidneys aren't working too well.

Creatinine is much much more reliable. BUN is influenced by nutritional status and is less reliable. I wouldn't worry about it if the BUN was slightly elevated and creatinine clearance was normal.

Glucophage is an anti-hyperglycemic agent. It prevent high blood sugar by decreasing the sugar your liver produces, decreasing the sugar your intestines absorb, and improving the sensitivity of your cells to insulin. It's also being used now for patients with PCO (polycystic ovary disease). I'd say he's doing it for PCO'ish hormone levels (which also involves insulin resistance somewhere in there). Not entirely sure of course, since I don't know your full history.