First you need to know what the half-life of glucophage is, which I don't. I know with humalin-R, it's about 2 hours. So vary it to correspond with the effective half life of glucophage.. i.e. How long does it keep lowering your glucose? Once you know that, then glucose disposal agents all are used basically the same way. Take your blood sugar reading after the time has passed, and if it's above 60, then take some more. Judge by how much it dropped the first time as to whether you should up your dose or lower it. I have no idea of the correct dose for glucophage. When your blood sugar is below 60, then stop taking any glucose disposal agents and let your body take you the rest of the way there. Once you get below 50, you should begin to see ketones present in the blood, that's the general place that most people enter ketosis. You may be a little higher, and you may begin to see some ketones present from dietary fat. The general rule, though, is that once your blood sugar gets below 50, you will enter ketosis and stop burning glucose for energy. Anytime you are using any disposal agent like glucophage, and especially if you are using insulin, always have some type of glucose replacement nearby in case you need it. If you begin to feel disoriented, or really sluggish, then you might consider taking some glucose to get your blood sugar back up.. Be careful not to overreact though.. I was using insulin, and after my first dose, I was still above 80, so I took 3 more ius. About 2.5 hours later, I was feeling weird, and kind of out of it, and took my blood sugar.. It was 46.. I should have just waited and took it again in 30 minutes to make sure it didn't go any lower, but instead I took a glucose tablet.. It had 4g of carbs, 15cal of all glucose, and 30 minutes later my blood sugar was at 77. I guess to sum up.. Once your glucose level falls below 60, don't take anything else. Check the glucophage to see how often it is to be taken, and take a dose at that interval checking blood sugar immediately prior to taking it until your blood sugar is below 60. Good luck.