Unless it was much higher a few hours earlier and has now gone DOWN to 200, this value is NOT acutely dangerous. No emergent treatment is needed. Note I said it is not ACUTELY dangerous. It is a very poor number to maintain on a regular basis as it may lead to LONG-TERM problems.
Feel free to ask a follow-up question.
SOrry, I didn't realize this was connected to the seroquel question. However it does not change my answer. I would not take an additional metformin for this. I would simply continue to monitor the sugar. You should have a plan arranged with your MD regarding at what point he feels additional treatment is necessary.