Yes, you may take them both at the same time. My doc prescribed 500 mg ER 4x in the evening. I started dividing it 2/2 AM/PM - but half the time forget and take them all in the evening. I've noticed no difference in bg readings that I could attribute to timing of my metformin.
Thanks to all for your responses! I ended up going to bed and only taking one so this morning my bs was 103 which may or may not be because of only having 1/2 dosage yesterday. Another time it was only 95 after missing a dose, so who knows.
I take my Metformin 3 times a day, usually one when I wake up, one around 9-10 am and the last before bed. I often forget the one in the middle of the morning. I usually take it as soon as I remember. I think you can do that with metformin but I would not do it with other jobs like sulfyurea drugs.