Hello, I'm so very sorry you feel so desperate. Metformin is known in overdoes to have instances of lethal but that is not a guaranteed side effect and only occurs in a small percentage of patients. The most common side effect is called lactic acidosis which is when you have lactic acid buildup in your bloodstream and muscles. This typically causes muscle cramps, nausea, and vomiting. There are cases of death as a side effect of overdose but there is also a specific case where a diabetic woman survived 65 grams of the active drug ingested in pill form.
The pills are typically in the following solid dosage:. 500 mg; 750 mg; 850 mg; 1000 mg. Since at the lowest dosage (assuming these are not compounded) you would have 360 g of metformin you would be taking a lot of pills to ingest them all. Because of the nausea and vomiting associated with the side effect I would suspect that you would regurgitate and not be able to keep the drug down. This happens with many overdose attempts and is neurological and the body's way of protecting itself.
I do not recommend taking prescription or OTC medication, including an overdose of metformin as a way to catch the bus. Your most likely outcomes would be nausea, vomiting, renal failure, disorientation, agitation and muscle and leg cramps and although the dosage could be lethal, the side effects would be very painful and could leave you alive but with dialysis necessary.
Here is an article regarding a suicide attempt with metformin which did result in death but also cited are the low instances of death from metformin overdose.
A 29-year-old man with no history of diabetes ingested over 60 grams of metformin in a suicide attempt. He presented to the emergency department with acute renal insufficiency, severe lactic acidosis, and rapidly-progressive hyperglycemia. The patient’s ...
www.ncbi.nlm.nih.gov